1143 results about "Electronic packaging" patented technology

The invention relates to the technical field of electronic packaging, in particular to a welding process applied to a double-mesa device. The technology comprises the following steps that firstly, a heat conduction model of a double-table-board device is built, a temperature field prediction system is built in combination with measured data, secondly, an asymmetric double-pulse-current welding strategy is adopted, differential pulse waveforms are loaded to an upper table board and a lower table board respectively, independent temperature control over all welding areas is achieved, a temperature difference closed-loop feedback mechanism is introduced in the process, and the temperature field prediction system is obtained. Pulse parameters are dynamically adjusted according to real-time temperature deviation, a stress prediction and weld penetration monitoring module is used for assistance, the welding spot forming quality and heat stress balanced release are ensured, a staged annealing type cooling mode is adopted after welding, and the structural stability is improved. The method can be widely applied to MEMS modules, SiC power devices and heterogeneous chip laminated packaging double-mesa structure devices, and has the advantages of being high in welding precision, high in reliability and wide in process adaptability.

The invention discloses an electronic packaging heat dissipation substrate and a processing technology and application thereof. The electronic packaging heat dissipation substrate comprises a copper-clad diamond copper plate, a diamond sheet located on the copper-clad diamond copper plate and a first copper layer covering the diamond sheet. The copper-clad diamond copper plate comprises a diamond copper core material and a copper layer located on the surface of the diamond copper core material. The diamond copper core material and the copper layer form a composite board with a copper layer-core material-copper layer sandwich structure; and the copper-clad diamond copper plate, the diamond sheet and the first copper layer are connected into a whole through brazing. According to the electronic packaging heat dissipation substrate, the peeling and cracking risks can be reduced, and the problem of low heat transfer efficiency is solved.

The invention discloses a production quality evaluation method for a gold bonding wire, and relates to the technical field of microelectronic packaging, and the method comprises the following steps: obtaining a surface image of the gold bonding wire through a high-resolution image collection system; performing preprocessing on the image data based on the acquired image to eliminate noise and enhance contrast; through the image data, extracting surface topography gradient features by using morphological operation, and quantifying microstructure changes of the surface of the gold wire; extracting texture energy characteristics through wavelet multi-scale decomposition, and analyzing distribution characteristics of surface textures from different scales; self-adaptive fusion is carried out on the morphological gradient features and the texture energy features, and the feature expression of the defect area is enhanced by dynamically adjusting the weight; dividing the boundary of a defect region by adopting an adaptive threshold segmentation method, and separating a normal region from an abnormal region; and extracting geometric and textural features of the defect region obtained by segmentation, realizing automatic discrimination of defect types through a classification model, and outputting a quality evaluation result.

The invention discloses a method for preparing regenerated flame-retardant high-shrinkage polyester by a methanol alcoholysis method, and belongs to the technical field of polyester. The method comprises the following steps: (a) mixing the waste polyester fabric with methanol, and carrying out catalytic depolymerization to obtain a regenerated DMT mixed solution; (b) carrying out impurity separation and methanol recovery treatment on the regenerated DMT mixed solution, and then carrying out cooling crystallization, centrifugal drying and rectification purification treatment to obtain pure DMT; (c) carrying out transesterification on pure DMT, ethylene glycol, a transesterification catalyst and a DEG inhibitor; (d) after the ester exchange reaction, adding CEPPA-EG and IPA-EG for copolymerization; adding a polymerization catalyst, a stabilizer and an antioxidant for polymerization reaction to obtain a modified polyester melt; and (e) granulating and drying to obtain the slices. The regenerated polyester prepared by the method has multiple functions of flame retardance, high boiling water shrinkage, low-temperature dyeing and the like, and is suitable for the fields of high-end clothing, automotive trim, electronic packaging materials and the like.

A microelectronics package comprises a substrate comprising at least two conductive layers that are separated by a first dielectric. At least one island comprising a magnetic material is embedded within the dielectric between the two conductive layers. An inductor structure extends within a via in the at least one island. The via extends between the two conductive layers. The inductor structure comprises a conductive wall along a sidewall of the via, and wherein the conductive wall surrounds a second dielectric and is electrically coupled to the two conductive layers.

The invention provides a diode packaging defect tracing method and system based on correlation analysis, and relates to the technical field of electronic packaging process optimization and quality control. And extracting the frequency domain characteristic value of the X-ray image and carrying out correlation analysis in combination with the process parameters to determine a key abnormal process parameter combination causing the cavity defect. Therefore, the accuracy and reliability of defect tracing can be comprehensively improved, abnormal process parameters can be quickly positioned, and packaging process conditions can be optimized, so that the occurrence rate of cavity defects is effectively reduced, and the quality and performance of diode packaging are improved; the problem that root process parameters are difficult to accurately position due to cavity defects caused by mismatching of welding temperature and pressure can be solved to a certain extent.

The invention relates to a bionic Al / SiC composite material with a three-dimensional network multilevel structure and a preparation method of the bionic Al / SiC composite material, and belongs to the technical field of new material preparation. According to the method, through the collaborative process of freeze casting and organic foam impregnation, the problem that in the prior art, the multilevel aperture and the complex network structure are difficult to cooperatively regulate and control is solved. The preparation method comprises the following specific steps: preparing tert-butyl alcohol-based ceramic slurry, impregnating the slurry with polyurethane foam, performing freeze casting molding, removing a solvent through freeze drying, performing high-temperature sintering to form SiC ceramic with a three-dimensional reticular hierarchical pore structure, and finally preparing the Al / SiC composite material through a vacuum pressure infiltration process. Wherein a sintering aid is added into the slurry, so that the sintering temperature is obviously reduced; the specification (40-60 ppi) of polyurethane foam, the solid phase content (20-30 vol.%) of slurry, the freezing speed (0-90 DEG C) and the content (5-20 wt.%) of a sintering aid are regulated and controlled. And the cross-scale collaborative design of micron-scale directional holes and millimeter-scale mesh holes is realized. The Al / SiC composite material prepared by the invention has the advantages that the compressive strength, fracture toughness and other properties are obviously higher than those of the traditional single-aperture porous ceramic, and the Al / SiC composite material is suitable for the fields of manufacturing and energy absorption of precise instruments, electronic packaging and optical devices.

The invention provides a polyimide-based dielectric heat-conducting composite material and a preparation method thereof.The preparation method comprises the steps that a hexagonal boron nitride nanosheet is modified through polydopamine to obtain a modified boron nitride nanosheet (MBN), and the modified boron nitride nanosheet (MBN) is mixed with a polyamide acid (PAA) solution to obtain an MBN / PAA solution; mBN is directionally distributed in PAA nanofibers through an electrostatic spinning technology, meanwhile, dispersion liquid of silver wires is electrostatically sprayed, and the silver wires serve as a bridge, so that a heat conduction path is constructed under the condition that less filler is doped; finally, the MBN-AgNW / PI dielectric heat-conducting composite material is prepared through a staggered stacking-compression molding-thermal imidization technology, and the prepared composite material is good in heat conductivity, low in dielectricity and high in insulativity and has huge application potential in electronic packaging equipment.

The invention relates to the technical field of flame-retardant materials, and particularly discloses a graphene-modified flame-retardant polyurethane material and a preparation method thereof.The graphene-modified flame-retardant polyurethane material is prepared from, by weight, 60-70 parts of polyhydric alcohols, 30-40 parts of isophorone diisocyanate, 0.4-0.8 part of dibutyltin dilaurate, 3-6 parts of dimethylolpropionic acid, 15-20 parts of composite flame retardant, 2-4 parts of 1, 3-butanediol, 2-4 parts of 1, 3-butanediol, 2-4 parts of 1, 3-butanediol, 2-4 parts of 1, 3-butanediol, 2-4 parts of 1, 3-butanediol, 2 and 1 to 3 parts of 1, 4-butanediol and 1 to 3 parts of perfluorooctyltriethoxysilane. The preparation method comprises the following steps: 1) preparing castor oil-based polyester polyol through hydroxylation reaction and polycondensation; 2) taking graphene oxide as a core, grafting phosphorus and nitrogen flame-retardant groups and carrying out silane-titanate synergistic modification to prepare a composite flame retardant; 3, polyhydric alcohol and isocyanate are pre-polymerized, then the chain extender, the composite flame retardant and the auxiliaries are sequentially added, and curing molding.The material has low smoke and excellent flame retardance, mechanical property and hydrophobic stability through the synergistic effect of graphene and a phosphorus-nitrogen flame-retardant system, and is suitable for the field of flame-retardant high polymer materials for buildings, electronic packaging and the like.

The present invention relates to an intrinsically high thermal conductivity-low dielectric polyimide film, its preparation method, and applications. The polyimide is composed of polyimide A and polyimide B through blending or grafting. The polyimide film of the present invention has intrinsically high thermal conductivity, low dielectric constant and loss, and excellent heat resistance and mechanical properties. It has broad application prospects in integrated circuits, electronic packaging, and other fields.

The invention relates to the technical field of high-temperature-resistant and high-thermal-conductivity epoxy electronic packaging adhesives, discloses a preparation method of a core-shell Al2O3-coated SiO2 filler and application of the core-shell Al2O3-coated SiO2 filler in epoxy packaging, and designs the preparation method of the core-shell structure filler Al2O3-coated SiO2 by chemically modifying the surface of the Al2O3 filler through high-temperature-resistant SiO2. The high-temperature-resistant SiO2 shell layer is modified on the surface of Al2O3, so that the interface wettability between the epoxy resin and the filler is promoted, the binding force between the filler and the epoxy resin is increased, the dispersity and fluidity of EMC are improved, meanwhile, the 175-DEG C bending strength of the epoxy resin is improved, and the high-temperature usability of the epoxy resin is greatly improved. And finally, the core-shell structure Al2O3-coated SiO2 can easily form a heat-conducting path among the filler, the interface and the matrix resin, so that the overall heat-conducting property of the composite material is improved, the low thermal expansion coefficient of the SiO2 shell layer is improved, the thermal stress is buffered, the temperature resistance is improved, and the core-shell structure Al2O3-coated SiO2 can be widely applied to packaging of semiconductor integrated circuits.

The invention discloses a preparation process of a high-performance Cu-Ni-Fe alloy calculated and designed based on a first principle, and relates to the technical field of alloy material preparation. According to the process, a precise Cu-Ni-Fe ternary alloy thermodynamic database is constructed by combining a first principle with a CALPHAD method, a multivariate phase diagram is calculated based on the database to determine a component range, then optimized components of a work function, an elastic constant and a thermal expansion coefficient are calculated through the first principle, and a finished product is obtained through smelting, heat treatment and forming machining. The final alloy is composed of, by atomic percent, 30%-75% of Cu, 10%-30% of Ni and 10%-30% of Fe, the tensile strength is larger than or equal to 816.4 MPa, the total elongation at break is larger than or equal to 34.27%, the thermal expansion coefficient is smaller than 20 * 10 <-6 > / K, the excellent mechanical property and thermal stability are achieved, the problems that component design is blind and performance fluctuation is large in a traditional process are solved, and the alloy is suitable for the fields of ocean engineering, electronic packaging and the like.

The invention relates to a preparation method of a magnetic field-electric field synergistically driven Fe3O4-loaded graphene three-dimensional interlocking network / metal composite material, and belongs to the field of electronic packaging materials. An alternating magnetic field and a direct-current electric field are applied in the solidification process of metal melt, Lorentz force is used for driving graphene nanosheets loaded with Fe3O4 to rotate directionally and be arranged vertically, meanwhile, the electric field induces dissociation of graphene edge functional groups, chemical bonding with a metal matrix is enhanced, and a space interlocking heat conduction network is formed. The graphene reinforced metal composite material is obviously superior to a traditional graphene reinforced metal composite material and is suitable for a heat dissipation substrate of aerospace electronic equipment.

The invention relates to the technical field of solder paste, in particular to halogen-free soldering flux for solder paste and a preparation method of the halogen-free soldering flux. The halogen-free soldering flux for the solder paste comprises the following raw materials in parts by mass: 20-40 parts of hydrogenated rosin, 1-5 parts of maleic anhydride, 0.1-0.4 part of p-toluenesulfonic acid, 1-5 parts of activated mesoporous silica, 10-20 parts of a composite organic acid active agent, 5-10 parts of a thixotropic agent, 1-3 parts of a tackifier, 1-2 parts of a pH regulator, 1-2 parts of a surfactant, 1-2 parts of a chelating agent, 1-2 parts of an antioxidant and 50-80 parts of an organic solvent. Through the innovative component design and the preparation process, the technical contradiction existing in the field of halogen-free scaling powder for a long time is effectively solved, and an ideal material solution is provided for high-reliability electronic packaging.

The invention discloses a high-thermal-conductivity PI / ceramic composite insulation packaging sheet and a preparation method thereof, and relates to the technical field of electronic packaging. The high-thermal-conductivity PI / ceramic composite insulation packaging sheet is obtained by mixing a modified polyimide solution and modified ceramic particles according to the mass ratio of (9-13): 1 and then performing high-temperature curing. The modified polyimide solution is obtained by mixing a dianhydride monomer and a diamine monomer in a molar ratio of 1: 1, and 2-methyl-2-acrylic acid-2, 3-dihydroxy propyl ester accounting for 5-10% of the total molar weight, and adding a catalyst for catalysis; the modified ceramic particles are obtained by adding hydroxymethyl acrylamide into a ceramic suspension, mixing, filtering, washing and drying. The packaging sheet prepared by the invention has high thermal conductivity, keeps stable at a relatively high temperature, is not easy to thermally deform, and has relatively high stability.

The invention belongs to the technical field of electronic packaging defect detection, and particularly discloses a semiconductor packaging welding spot defect detection system and a detection method thereof.The system comprises an infrared excitation module and an ultrasonic signal processing module; a to-be-detected packaging sample wafer is arranged on a laser emergent light path of the infrared excitation module during detection, and is positioned in a detection focus area of the ultrasonic signal processing module; the infrared excitation module scans a to-be-tested packaging sample wafer by using the output infrared laser so as to thermally excite the internal structure of the to-be-tested packaging sample wafer and primarily generate an ultrasonic signal; when the infrared excitation module scans, the ultrasonic signal processing module synchronously detects a first ultrasonic signal generated by each scanning position point on the to-be-detected packaging sample wafer, and determines a welding spot defect detection result of the to-be-detected packaging sample wafer based on the first ultrasonic signal of each scanning position point. According to the invention, the precision and sensitivity of semiconductor packaging welding spot defect detection can be effectively improved.

The invention discloses a protruding conductive microsphere and a pretreatment method thereof. The pretreatment method specifically comprises the steps of roughening treatment, protruding and interface activity treatment, sensitization treatment, activating treatment and chemical plating. In the protruding and interfacial activity treatment, by adding an interfacial agent, the electronegativity of the surfaces of the microspheres is enhanced, electrostatic adsorption with positively charged nickel nanoparticles is generated, and meanwhile, agglomeration of the nickel nanoparticles on the surfaces of the polymer microspheres is effectively prevented through the steric hindrance effect; therefore, a nickel nanoparticle bulge structure which is high in density, uniform in distribution and firm in combination is formed on the surface of the polymer microsphere. The method effectively solves the problems that a traditional conductive microsphere coating is prone to cracking and falling off, poor in dispersity and the like, the prepared protruding conductive microspheres have the outstanding advantages of being high in coating binding force, excellent in conductivity, good in dispersity, not prone to agglomeration and the like, the technological process is simple, mass production is easily expanded, and the method is suitable for large-scale production. The anisotropic conductive adhesive film has a wide commercial application prospect in the field of electronic packaging such as anisotropic conductive adhesive films.

The invention relates to the field of electronic packaging materials, and discloses an epoxy molding compound as well as a preparation method and application thereof. Based on the total weight of the epoxy molding compound, the epoxy molding compound contains 13 to 20 weight percent of epoxy resin, 6 to 14 weight percent of a curing agent, 0.05 to 0.2 weight percent of a curing accelerator, 70 to 78 weight percent of filler, 0.1 to 1 weight percent of a coupling agent, 0.1 to 4 weight percent of a stress modifier, 0.1 to 2 weight percent of a release agent, 3 to 8 weight percent of a flame retardant, 0.01 to 0.3 weight percent of an ion trapping agent and 0.3 to 0.6 weight percent of a coloring agent, wherein the curing accelerator is 2-undecylimidazole, and the curing accelerator is 2-undecylimidazole; and the coupling agent is gamma-mercaptopropyl trimethoxy silane and / or gamma-glycidyl ether oxypropyl trimethoxy silane. The invention further discloses a preparation method of the silane coupling agent. The epoxy molding compound is simple to prepare, shows relatively high bonding performance and demolding performance when being used for packaging semiconductor components, and has relatively high operability and reliability.

The invention discloses a nylon composite material and a preparation method thereof. The nylon composite material is prepared from polyamide, GF-POSS-1, GF-POSS-2, a toughening agent, an antioxidant and a lubricating agent. The GF-POSS-1 is obtained by reacting an aminated solid glass fiber and epoxidized POSS in a weight ratio of 5: (0.5-2); the GF-POSS-2 is obtained by reacting epoxidized hollow glass fibers and aminated POSS according to a weight ratio of 5: (0.5 to 2). The nylon composite material disclosed by the invention has excellent comprehensive properties of high tensile strength, high toughness, low dielectric constant and low dielectric loss, and is suitable for high-end scenes such as 5G communication and high-frequency electronic packaging.

The invention relates to aluminum borosilicate glass with low dielectric constant and low dielectric loss and a preparation method and application thereof, and relates to the field of aluminum borosilicate glass manufacturing, the aluminum borosilicate glass comprises the following main components by molar percentage: 60%-85% of SiO2, 0-10% of Al2O3, 2%-30% of B2O3, 0-20% of alkaline earth oxide, 0-10% of alkali metal oxide, 0-10% of ZnO, 0-1% of P2O5 and 0-2% of TiO2 and / or ZrO2; during preparation, the raw materials are melted, clarified and homogenized according to the corresponding dosage, and then are annealed for 3-8 hours at the temperature of 600-650 DEG C. The obtained aluminum borosilicate glass can reduce transmission loss during high-frequency signal transmission, has dielectric constant stability which does not exceed + / -0.5 change under a 1-30 GHz signal test, and can be applied to preparation of integrated antennas, electronic packaging and micro electro mechanical system packaging.

The invention discloses a preparation method of angular aluminum nitride large-particle powder, which comprises the following steps: weighing raw material aluminum powder, aluminum nitride powder and a sintering aid according to a ratio, uniformly mixing, carrying out compression molding, carrying out combustion synthesis on a raw material blank in a high-pressure nitrogen atmosphere to obtain aluminum nitride ceramic, and crushing and screening to obtain the angular aluminum nitride large-particle powder of 20-200 mu m. According to the invention, one-step synthesis and sintering of aluminum nitride are realized by utilizing combustion reaction heat release of aluminum powder and nitrogen, the method has the characteristics of simple process and low preparation cost, and the prepared angular aluminum nitride large-particle powder can be used as a high-thermal-conductivity filler for electronic packaging.

The invention discloses a multi-chip CCGA packaging welding column failure risk evaluation method, and belongs to the technical field of electronic packaging and reliability analysis, and the method comprises the steps: building a finite element analysis model through obtaining the geometric and material parameters of a multi-chip CCGA packaging structure; non-uniform working conditions are set, boundary conditions and constraints are applied, and non-uniform distribution thermal stress of the welding column is obtained through thermal cycle loading analysis; key data are extracted, the fatigue life of the welding column is calculated through a Coffin-Manson thermal fatigue model, and a life matrix is determined; the welding column damage amount is calculated based on a thermal fatigue model and a linear accumulation damage theory, and a damage matrix is obtained; welding column failure is judged according to the damage matrix, and a risk level matrix is obtained. According to the method, the stress distribution and failure mechanism of the welding column under the multi-chip coupling scene can be rapidly and accurately evaluated in the design and early verification stage according to the actual working condition, and scientific support is provided for research and development of high-reliability electronic products.

The invention relates to the technical field of organic silicon materials, and discloses high-thermal-conductivity low-dielectric organic silica gel and a preparation method and application thereof.The high-thermal-conductivity low-dielectric organic silica gel is prepared from a component A and a component B. The component A is prepared from, by weight, 35-45 parts of vinyl polysiloxane, 40-50 parts of vinyl silicone resin, 5-20 parts of modified boron nitride, 0.75-1.25 parts of a flatting agent, 1.5-2.5 parts of a defoaming agent and 0.05-0.15 part of a platinum catalyst; and the component B comprises the following components in parts by weight: 15-20 parts of vinyl polysiloxane, 60-85 parts of hydrogen-containing silicone oil and 0.05-0.15 part of an inhibitor. According to the scheme, a continuous and effective 3D heat conduction network is constructed through modified boron nitride, the heat conduction performance of the organic silica gel is improved, meanwhile, covalent interaction is formed between the modified boron nitride and other matrixes, interface bonding is high, the dipole polarization effect at an interface is reduced, the dielectric constant is reduced, and the organic silica gel is quite suitable for the field of electronic packaging.

The present application discloses a semiconductor bonding auxiliary operation robot and equipment, which relates to the field of microelectronic packaging technology. The semiconductor bonding auxiliary operation robot is composed of a machine platform, a control device, a robotic arm, a vision positioning device, a loading tool, a gripping tool, a suction tool, and a touch screen tool. The robotic arm is installed on the machine platform, and the vision positioning device is installed on the robotic arm. The gripping tool, the suction tool, and the touch screen tool are connected to the robotic arm. The gripping tool is used to grip the upper sample / lower sample / sample after bonding. The loading tool has a loading station for placing the upper sample / lower sample. The loading station is provided with a relief groove to avoid the finger gripping action. The suction tool is used to suck the back of the upper sample / the edge of the lower sample / the back of the sample after bonding. It realizes the automatic loading, bonding, and unloading of the bonding equipment, improves efficiency and reduces errors. At the same time, specific gripping and suction methods are adopted to protect the samples before and after bonding, increasing the operation flexibility.

The invention discloses a modified phenolic resin and a preparation method thereof, and belongs to the technical field of phenolic resins, the modified phenolic resin comprises the following raw materials by mass: 100 parts of phenol, 140-145 parts of a formaldehyde aqueous solution, 25-30 parts of gradient topology phosphonate, 15-17 parts of hyperbranched siloxane, 12-14 parts of a dynamic borate cross-linking agent, and 3-4 parts of hexamethylenetetramine. Through the synergistic effect of the gradient topology phosphonate, the hyperbranched siloxane and the dynamic boric acid ester cross-linking agent, the flame retardance, the thermal stability, the mechanical property and the dynamic function of the phenolic resin are comprehensively improved, and the environmental protection property of the phenolic resin is remarkably superior to that of a traditional technology. The experimental data fully verifies the inseparability and synergistic interaction among innovation points, and the technical combination and effect are non-obvious and accord with the creativity requirement of the patent. In addition, the application potential of the resin in the fields of aerospace, electronic packaging and the like further highlights the industrial value of the resin.

The invention relates to the field of low dielectric materials, and particularly discloses a BCB-containing fluorene derivative as well as a preparation method and application thereof, and the derivative is specifically shown as follows: in substitution sites 1-10 of fluorene and / or fluorene derivative, substituent groups R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from at least one of hydrogen atoms, alkyl groups and aryl groups, and the substituent groups R9 and R10 comprise at least one BCB group. According to the present invention, the BCB group is introduced to the R9 and / or R10 substituent group of the fluorene and / or the fluorene derivative, such that the obtained BCB-containing fluorene derivative has characteristics of good thermal stability and low dielectric property. Meanwhile, the performance of the fluorene derivative containing BCB can be accurately optimized by flexibly regulating and controlling the types of substituent groups, the number of BCB groups on R9 and R10 substituent groups and the structure of the substituent group on the fluorenyl group, so that the problem of meeting low dielectric materials in the fields of high-performance PCBs, electronic packaging and the like in the prior art is solved.

The invention relates to the technical field of electronic packaging materials, in particular to a phthalonitrile modified thermosetting resin composition containing a siloxane structure and application of the phthalonitrile modified thermosetting resin composition in the electronic packaging materials. The composition comprises multifunctional epoxy resin, XYLOK phenolic resin, a curing accelerator, a modifier and an inorganic filler, and the modifying agent is eugenol phthalonitrile trisiloxane. The modifier disclosed by the invention has good mechanical compatibility and dispersity in matrix resin; when the epoxy resin is applied to a thermosetting resin system, the processability can be improved, and the toughness of a cured product can be effectively improved while the glass-transition temperature is increased, so that the cured product has excellent bending property; the composition has excellent thermal stability, low bending modulus, good impact performance and humidity and heat resistance after being cured, the glass transition temperature of the composition is effectively improved, the comprehensive performance of resin is remarkably improved, and the composition is suitable for improving the packaging reliability and environmental stability of semiconductor devices.

The invention belongs to the technical field of electronic packaging and welding materials, and relates to lead-free solder powder for reflow soldering and a preparation method of the lead-free solder powder. The lead-free solder powder is based on a Sn-Ag-Cu alloy system, and melt purification, beta-Sn grain refinement and interface IMC stabilization are achieved by compositely adding trace Ce and Ni elements. The Sn-Cu-Ce alloy comprises the following components in percentage by mass: 2.9%-3.1% of Ag, 0.45%-0.55% of Cu, 0.01%-0.10% of Ce, 0.01%-0.05% of Ni and the balance of Sn and impurities. During preparation, a Ce-Ni intermediate alloy is adopted to introduce microalloy elements, and the spherical solder powder is obtained through vacuum melting, inert gas atomization and surface treatment. The obtained solder powder is low in oxygen content, good in wettability, slow in interface IMC growth after backflow, high in welding spot strength and excellent in thermal cycle reliability, and is suitable for the field of high-reliability electronic packaging.

The invention discloses a preparation method of a self-adaptive anti-electromagnetic interference composite material, which comprises the following steps: firstly, etching a Ti3AlC2 precursor through a LiF / HCl solution to prepare few-layer MXene powder; the preparation method comprises the following steps: preparing a carbon nanotube / Ti < 3 > C < 2 > T < x > MXene powder / chitosan / polyethyleneimine dispersion liquid through a chemical crosslinking method; and finally, carrying out a freeze drying process to obtain the carbon nanotube / Ti < 3 > C < 2 > T < x > MXene powder / chitosan / polyethyleneimine composite aerogel. The carbon nanotube / Ti < 3 > C < 2 > T < x > MXene powder / chitosan / polyethyleneimine composite aerogel prepared by the preparation method disclosed by the invention is excellent in electromagnetic shielding performance and high in absorption capacity, and can meet the application requirements in the fields of aerospace, electronic packaging and the like. Meanwhile, the strain sensing capacity is achieved, the sensitivity is outstanding under different strains, repeatability and linearity are good, the capacity of distinguishing different strain magnitudes is achieved, and the strain sensor is suitable for scenes needing dynamic and quantitative strain monitoring. The composite material has efficient electromagnetic shielding performance and excellent sensing performance, and has a wide application prospect in practical application.

The invention relates to the field of electronic paste, and provides high-performance electronic paste based on a graphene composite material and a preparation method of the high-performance electronic paste. The slurry comprises a surface modified graphene / silicon carbide nanowire hybrid, a carbon-coated silver nanorod, epoxy resin, a polyamide curing agent, a KH-550 coupling agent, polyvinylpyrrolidone, fumed silica, polyether modified polydimethylsiloxane and a compound solvent. By constructing a multi-scale conductive network and an interface enhancement structure, excellent conductivity and shear strength of the slurry are realized. The preparation method comprises the steps of in-situ synthesis and surface modification of the graphene hybrid filler, deposition preparation of the carbon and silver nanorods, and a multi-stage dispersion compounding process of all the components under specific temperature control and shearing conditions, and finally the electronic paste which is stable in structure and excellent in performance is formed and is suitable for scenes such as high-reliability electronic packaging and conductive bonding.