Preparation method and application of selective electro-deposition copper-based array structure

Abstract

The invention provides a preparation method and application of a selective electro-deposition copper-based array structure, the selective electro-deposition copper-based array structure comprises a water phase and an oil phase, the water phase comprises 0.1-0.5 mol / L of copper sulfate, 0.01-0.05 mol / L of copper chloride, 2-9 [mu] mol / L of a nitrogen-containing heterocyclic surfactant, 0.1-1.0 mmol / L of an anionic surfactant and 0.01-0.1 mol / L of sulfuric acid, and the oil phase comprises a low-conductivity organic solvent. A cathode is connected with a substrate to be plated, an anode is connected with an inert electrode, an external direct-current power supply is applied, and the copper column or copper dendrite array is formed through selective electro-deposition under the template-free condition by regulating and controlling the current density. By means of the technical scheme, template-free one-step forming is achieved, ultra-high-density bonding pad low-resistance and low-thermal-resistance interconnection can be achieved under the room-temperature / low-temperature condition, meanwhile, the thermal expansion mismatch problem is solved, the process is simple, and cost is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal micro-nano structure preparation technology, and particularly to a preparation method of a selective copper-based array structure and application thereof. BACKGROUND

[0002] With the rapid development of emerging technologies such as 5G communication, artificial intelligence, and Internet of Things, electronic devices are evolving towards miniaturization, integration, and high performance. In the field of integrated circuits (IC), chip feature sizes continue to shrink under the driving of Moore's Law, and 3D integration technologies such as chip stacking and system-level packaging are widely used, enabling the packaging density of electronic terminals such as mobile devices and wearable devices to continue to increase. Taking smartphones as an example, the pin density of single-chip packaging has increased by more than 40% in the past five years, and the typical packaging pitch has evolved from 50 μm to less than 10 μm, posing stringent requirements on interconnection technologies. Traditional electronic interconnection technologies, such as wire bonding and solder bumping, gradually show limitations when facing ultra-high-density packaging. For example, the solder bonding process relies on lead-based or lead-free solder alloys such as the Sn-Ag-Cu system, which forms a metallurgical bond by heating to 200-260°C. Although it can form a reliable electrical connection, it has the following inherent defects.

[0003] First, there is the issue of high-temperature process compatibility. With the extensive use of heat-sensitive materials such as organic substrates, flexible circuit boards (FPCs), and low-dielectric constant (Low-k) dielectric layers in three-dimensional packaging, traditional high-temperature bonding easily leads to material thermal deformation and dielectric performance degradation. In particular, in stacked packaging, multiple high-temperature treatments can accumulate thermal stress, causing chip cracks and solder joint fatigue, among other reliability issues. Second, there is the bottleneck of micro-pitch interconnection. When the pad edge length is less than 10 μm and the pitch is less than 20 μm, the surface tension effect during solder melting can cause solder ball bridging and uneven size, making it difficult for existing processes to achieve ultra-high-density pad bonding with a 3 μm edge length and a 5 μm pitch, thereby restricting the development of next-generation fan-out packaging and 2.5D / 3D integration. Third, due to environmental and recycling challenges, the use of lead-containing solder is limited by the Restriction of Hazardous Substances Directive, and the multilayer alloy structure formed by the addition of elements such as bismuth and antimony in lead-free solder is difficult to separate efficiently during electronic waste recycling. The toxic gases (such as lead oxide and tin vapor) generated during high-temperature smelting processes put pressure on the environment, and the environmental costs of existing technologies are increasing year by year.

[0004] And the prior art preparation of copper dendrite / copper column array, need to rely on photoresist mask or nano template (such as alumina template) for selective deposition, need to glue, exposure, development and other 6-8 steps process, not only the process steps are complicated, and the template preparation cost accounts for 35%-40%, at the same time there is the risk of template residual pollution interface. SUMMARY

[0005] For the above technical problems, the application discloses a preparation method of selective electrodeposition of copper-based array structure and its application, which is applied to electronic packaging interconnection and high-efficiency thermal interface material, and has improvement in high temperature compatibility, electric and thermal conductivity performance and environmental protection.

[0006] To this end, the technical scheme adopted by the application is:

[0007] An electrolyte for selective electrodeposition of copper-based array structure, comprising an aqueous phase and an oil phase, the aqueous phase comprising 0.1-0.5 mol / L copper sulfate, 0.01-0.05 mol / L copper chloride, 2-9 μmol / L nitrogen-containing heterocyclic surfactant, 0.1-1.0 mmol / L anionic surfactant, inorganic acid, the oil phase comprising low conductivity organic solvent; the conductivity of the low conductivity organic solvent is less than 10 -5 S / m, the density is 0.75 g / cm 3 -1.25 g / cm 3 ; the inorganic acid is sulfuric acid, nitric acid or hydrochloric acid, the pH value of the aqueous phase is 1-3. The amount of inorganic acid added is determined according to the pH value of the aqueous phase.

[0008] Among them, copper sulfate as the main salt, supplemented by copper chloride (CuCl2·2H2O) to adjust the ion conductivity, the concentration of copper sulfate is 0.1-0.5 mol / L, providing the required concentration gradient for copper ion reduction; the concentration of copper chloride is 0.01-0.05 mol / L, and the Cl- dissociated therefrom can be adsorbed on the copper crystal surface to inhibit the irregular growth of dendrites. Adding sulfuric acid (H2SO4) can adjust the pH to 1.5-3.0, preferably 0.01-0.1 mol / L sulfuric acid concentration, inhibit the hydrogen evolution side reaction by hydrogen ion competition reduction, and at the same time improve the conductivity of the electrolyte. The surfactant adopts a complex system of nitrogen-containing heterocyclic cationic surfactant and sodium dodecyl sulfate (SDS, C 12 H25SO4Na), the nitrogen-containing heterocyclic cationic surfactant maintains the core role of crystal surface growth regulation, and the anionic surfactant cooperatively regulates the interface properties. The anionic surfactant forms a pre-micelle structure below the critical micelle concentration in the aqueous phase, and forms a complex micelle with the nitrogen-containing heterocyclic cationic surfactant, thereby enhancing the complexing ability of copper ions and cooperatively improving the current efficiency.

[0009] With the technical scheme, when an external direct current power supply is applied (cathode connected to the substrate and anode connected to the inert electrode), the high impedance of the oil phase forces the current to concentrate in the hydrophilic microzone exposed by the water phase. According to Ohm's law, the conductivity of the water phase is 10 times or more than that of the oil phase, resulting in an electric field strength of the hydrophilic microzone of 10 times or more than that of the oil phase. The above forms a 'current funnel' effect, and the current will preferentially pass through the water phase with low resistance (high conductivity) rather than the high-impedance oil phase, thereby causing the copper column and copper dendrite to grow rapidly along the water phase channel, and realizing selective electrodeposition of the copper-based array structure on the substrate. The method is simple and has good reliability. 6 6 The above forms a 'current funnel' effect, and the current will preferentially pass through the water phase with low resistance (high conductivity) rather than the high-impedance oil phase, thereby causing the copper column and copper dendrite to grow rapidly along the water phase channel, and realizing selective electrodeposition of the copper-based array structure on the substrate. The method is simple and has good reliability.

[0010] As a further improvement of the present application, the concentration of copper sulfate is 0.2-0.3 mol / L.

[0011] As a further improvement of the present application, the nitrogen-containing heterocyclic surfactant is benzimidazole or 2-mercaptobenzimidazole.

[0012] As a further improvement of the present application, the concentration of the nitrogen-containing heterocyclic surfactant is 5 μmol / L, and the concentration of the anionic surfactant is 0.5 mmol / L.

[0013] As a further improvement of the present application, the anionic surfactant is sodium dodecyl sulfate.

[0014] As a further improvement of the present application, the low-conductivity organic solvent is one or a mixture of two or more of cyclohexane, paraffin oil, silane, bromobenzene, and chloroform. Further, the low-conductivity organic solvent is one or a mixture of two or more of cyclohexane, paraffin oil, and polydimethylsiloxane.

[0015] As a further improvement of the present application, the volume ratio of the oil phase to the water phase is 1-3:1.

[0016] As a further improvement of the present application, the inorganic acid is sulfuric acid, and the concentration of the sulfuric acid in the water phase is 0.01-0.1 mol / L.

[0017] As a further improvement of the present application, the oil phase is a mixture of cyclohexane and paraffin oil in a volume ratio of 1:1 or pure cyclohexane.

[0018] The present application discloses a preparation method of a selective electrodeposited copper-based array structure, comprising: using the electrolyte for selective electrodeposition of a copper-based array structure as described above, connecting the cathode to the substrate to be plated, connecting the anode to the inert electrode, applying an external direct current power supply, and selectively electrodeposition to form a copper column or copper dendrite array under the condition of no template by adjusting the current density. When the current density is 5-20 mA / cm 2 , a copper column array is formed; and when the current density is 25-50 mA / cm 2 ​At this time, the copper dendrite array is formed.

[0019] By means of the difference between the water and oil in the electric conductivity, the copper column and the copper dendrite are grown and formed by electroplating in the water phase, the oil phase is not conductive and does not react, and thus the pores are formed, and the array structure is formed by combining the two together, and the array structure is formed once without a template, and the array morphology (the copper column and the copper dendrite array) can be controlled by the current density.

[0020] As a further improvement of the application, the potential in the electrodeposition process is -0.4 to -0.6 V vs. SCE, the deposition temperature is 25±5℃, and the deposition time is 5-30 min.

[0021] The application discloses the application of the preparation method of the selective electro-deposited copper-based array structure as described above to electronic packaging interconnection.

[0022] The application discloses an electronic packaging interconnection method.

[0023] The copper-based array structure comprises at least one of a copper dendrite array and a copper column array, the copper dendrite array has a multi-stage branch structure, and the copper column array grows perpendicularly to the substrate.

[0024] The application realizes high-performance interconnection under room temperature / low temperature conditions through the mechanical engagement and metallurgical bonding mechanism of the mortise and tenon structure, and the porosity of the solder joint is lower than 10%.

[0025] As a further improvement of the application, the surface of the copper-based array structure is coated with an activator, and hot-pressing sintering is performed in an air environment.

[0026] As a further improvement of the application, the sintering temperature is not higher than 200℃.

[0027] As a further improvement of the application, the hot-pressing pressure is 5-50 MPa, and the hot-pressing time is 15-30 min.

[0028] As a further improvement of the present application, the activator is at least one of ethanol, formic acid, and rosin.

[0029] The present application discloses an electronic packaging interconnection structure, comprising a chip, a substrate, and a copper-based array bonding layer sandwiched between the chip and the substrate, wherein the copper-based array bonding layer is prepared by the method for preparing a selective electrodeposited copper-based array structure as described above; the copper-based array structure comprises at least one of a copper dendrite array and a copper pillar array, the copper dendrite array has a multi-stage branch structure, and the copper pillar array grows perpendicularly to the substrate. Further, the length of the copper dendrite array is 100-500 μm, the diameter of the copper pillar array is 5-10 μm, and the height of the copper pillar array is 10-30 μm. The porosity of the solder joint obtained by using the technical scheme is less than 10%.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] First, by using the technical scheme of the present application, a template-free one-step forming is realized through water-oil two-phase electrodeposition, and the copper dendrite / copper pillar array obtained by electrodeposition breaks through the thermal mismatch bottleneck of traditional high-temperature interconnection, has low-temperature process compatibility, is environmentally friendly (lead-free, halogen-free, and organic solvent recovery rate > 95%), can realize ultra-high-density solder pad low-resistance, low-thermal-resistance interconnection under room temperature / low temperature conditions, and can eliminate the problem of thermal expansion mismatch, thereby meeting the core needs of the next generation of high-density and high-reliability electronic packaging.

[0032] Second, by using the technical scheme of the present application, the low-conductive shielding effect of the oil phase is used as a natural mask, the selective concentration (5-50 mA / cm 2 ) of the current density in the water phase exposure area is used to directly induce the directional reduction growth of copper ions, and a regular array structure is formed in one step, thereby saving the whole process of template preparation, reducing the process steps by more than 50%, reducing the cost by 60%, avoiding the defects introduced by the template, and realizing the regulation of the dendrite / copper pillar morphology through the coordination of the current density, thereby providing a low-cost and high-reliability template-free interconnection solution for high-density electronic packaging. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the top view of the copper pillar array obtained by selective electrodeposition in Example 1 of the present application.

[0034] Figure 2 is the top view of the copper dendrite array obtained by selective electrodeposition in Example 2 of the present application.

[0035] Figure 3 is the cross-sectional view of the copper pillar array hot-pressing solder joint in Example 3 of the present application.

[0036] Figure 4is the cross-sectional morphology of the copper dendrite array thermal compression welding spot in the embodiment 4 of the present application.

[0037] Figure 5 is the cross-sectional morphology of the copper column array cold compression welding spot in the embodiment 5 of the present application. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present application are further described in detail below.

[0039] The concept and technical effects of the present application will be described clearly and completely in combination with the embodiments below, so as to fully understand the purposes, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0040] Embodiment 1

[0041] A copper column array obtained based on selective electrodeposition, and the preparation steps are as follows:

[0042] Firstly, an electrolyte solution for selective electrodeposition of copper-based array structure is configured, the electrolyte solution comprises an aqueous phase and an oil phase, the aqueous phase: copper sulfate (CuSO4·5H2O) is used as a main salt, supplemented with copper chloride (CuCl2·2H2O), copper salt solution is configured by adding sulfuric acid (H2SO4) to adjust pH to 2.0, and benzimidazole and sodium dodecyl sulfate (SDS) are matched to obtain the aqueous phase solution. In the aqueous phase solution, the concentrations of the substances are as follows: copper sulfate 0.3 mol / L, copper chloride 0.03 mol / L, sulfuric acid 0.05 mol / L, benzimidazole 5 μmol / L, and sodium dodecyl sulfate (SDS) 0.5 mmol / L. The oil phase is compounded by equal volume of cyclohexane and paraffin oil. The volume ratio of the aqueous phase and the oil phase is 1:1.

[0043] Secondly, the cathode is connected to the substrate, the anode is connected to the inert electrode, the external direct current power supply is applied, and the current density is controlled to be 20 mA / cm 2 , and the deposition time is 20 min.

[0044] The top view morphology of the copper column array obtained in the embodiment is shown in Figure 1 It can be seen that the obtained array structure is uniform, the radial size of the copper column is about 10 μm, the copper column is vertically erected on the substrate surface, and there is obvious structural strength.

[0045] Embodiment 2

[0046] A copper dendrite array obtained based on selective electrodeposition, and the preparation steps are as follows:

[0047] First, the electrolyte for selective electrodeposition of copper-based array structure is configured, the electrolyte includes an aqueous phase and an oil phase, the aqueous phase: copper sulfate 0.2 mol / L, copper chloride 0.02 mol / L, sulfuric acid 0.08 mol / L, benzimidazole 5 μmol / L, sodium dodecyl sulfate (SDS) 0.5 mmol / L, and the pH value of the aqueous phase is 1. The oil phase is prepared by compounding equal volumes of cyclohexane and paraffin oil. The volume ratio of the aqueous phase to the oil phase is 3:1.

[0048] Secondly, the cathode is connected to the substrate, the anode is connected to the inert electrode, an external direct current power supply is applied, and the current density is controlled to be 50 mA / cm 2 , and the deposition time is 10 min.

[0049] The top view of the copper dendrite array obtained in the embodiment is shown in Figure 2 . In the process of high current density electrodeposition, the reduction rate of copper ions significantly exceeds the diffusion rate, driving the rapid growth of the array structure and forming a dendrite structure with multiple branches. Unlike traditional vertical copper pillars, such dendrites retain a large number of lattice defects due to rapid non-equilibrium growth, and present a collapsed stacking morphology.

[0050] Embodiment 3

[0051] A hot press bonding interconnection process based on copper pillar array, the specific steps for preparation are as follows:

[0052] On the basis of embodiment 1, after aligning two electrodes prepared with copper pillar array with each other, 10 MPa pressure is applied in the air environment, the temperature is raised to 200℃ at a rate of 10℃ / min, and hot press bonding is completed after 20 min of heat preservation, and the cross-sectional morphology of the solder joint is shown in Figure 3 . It can be seen that at this time, the single copper pillar presents a rigid vertical columnar structure. Under the action of pressure, the slight plastic deformation of the copper pillar can only form point contact connection at the tip or local area of the copper pillar on the surface of the upper and lower substrates. This limited deformation mode leads to the existence of significant voids in the solder joint, because the compressive stress is far below the yield threshold of the copper pillar, it is difficult to trigger large-scale dislocation slip and grain recombination, so the copper pillar mainly undergoes elastic deformation or local micro-plastic deformation, and cannot fill the pores between adjacent pillars by overall plastic collapse, resulting in high porosity of the overall solder joint.

[0053] Embodiment 4

[0054] A hot press bonding interconnection process based on copper dendrite array, the specific steps for preparation are as follows:

[0055] On the basis of embodiment 2, after aligning the prepared copper dendrite array, 10 MPa pressure is applied in the air environment, the temperature is raised to 200℃ at a rate of 10℃ / min, and hot press bonding is completed after 20 min of heat preservation, and the cross-sectional morphology of the solder joint is shown in Figure 4 .

[0056] Copper dendrites possess a unique flexible structure that endows them with excellent interface self-adaptive leveling ability. The ends of Cu dendrites with a length exceeding 100μm also have nanostructures, which can undergo plastic bending under pressure. By tilting and deforming, they fill the gaps. Their low-stiffness flexible structure breaks through the dependence of rigid copper pillars on the flatness of the substrate. With the self-adaptive leveling ability of multi-level branches, the interface porosity is significantly reduced compared with Example 3 under the same bonding conditions. It effectively solves the problem of non-uniform connection strength caused by traditional rigid structures and is a key structure to meet the requirements of high-quality hot-press bonding under low flatness conditions.

[0057] Meanwhile, the multi-level branching structure of the dendrites interlocks during hot pressing, forming a mechanically interlocking network that provides reinforcement similar to mortise and tenon joints. The nanostructure also significantly reduces the diffusion barrier, effectively promoting the sintering of the dendrite structure. Compared to rigid copper pillar arrays, the core advantage of copper dendrite arrays lies in their flexible structure adapting to interface non-flatness, while the nanonetwork accelerates metallurgical bonding, providing a solution for hot-press bonding of low-flatness array structures that combines process tolerance and superior performance.

[0058] Example 5

[0059] A cold-press bonding interconnect process based on copper pillar arrays, the specific steps of which are as follows:

[0060] Based on Example 1, after aligning the prepared copper pillar array, a pressure of 40 MPa was applied in air and held at room temperature for 20 minutes. The cross-sectional morphology of the solder joint is as follows. Figure 5 As shown, the rigid copper column array with a diameter of 15-20 μm exhibits significant mechanical interlocking characteristics. Due to axial pressure, the column tips undergo plastic deformation, and the deformation areas of adjacent columns interlock, forming a meshing interface with a width of 10-15 μm. This structure relies on the mechanical strength of the copper columns themselves to achieve interlocking. There are no obvious voids inside the weld joints, demonstrating the meshing advantages of rigid structures under cold pressing conditions.

[0061] Based on the comparison of the above embodiments 1-5, it can be found that the current density in the selective electrodeposition process is the core parameter for regulating the copper-based array structure. At a low current density, a rigid copper pillar array with a radial size of about 10 μm is formed (embodiment 1), while at a high current density, a flexible copper dendrite array with multi-level branches is formed due to the rapid reduction of copper ions (embodiment 2). The two types of structures show significant differences in thermal compression welding: the copper pillar array only has a tip point contact at a pressure of 10 MPa due to the rigid vertical structure (embodiment 3), the porosity of the welding point is high, and the mechanical interlocking depending on local plastic deformation is limited; while the copper dendrite fills the gap by tilting deformation at the same pressure (embodiment 4) due to the flexible multi-level branches, the porosity is greatly reduced, and the nanometer interface simultaneously promotes metallurgical bonding, showing excellent interface self-adaptability. In the cold pressure welding process (embodiment 5), the copper pillar top end is plastic deformed and embedded into each other under a high pressure of 40 MPa, forming a meshing interface with a width of 10-15 μm, which reflects the mechanical interlocking advantage of rigid structure at room temperature.

[0062] In summary, the flexible nanostructure of the copper dendrite array realizes the synergistic effect of "plastic deformation gap filling + nanometer diffusion strengthening" in thermal compression, while the copper pillar array realizes mechanical interlocking by plastic deformation in high-pressure cold compression, both of which are suitable for high-tolerance thermal compression scenarios and room-temperature high-strength interconnection scenarios with high interface flatness, highlighting the precise matching relationship between structure-process-performance under the regulation of current density. This feature makes the copper pillar / copper dendrite array show great flexibility and adaptability in electronic packaging interconnection and thermal interface material applications, providing new solutions for related fields.

[0063] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be regarded as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, some simple deductions or substitutions can be made without departing from the concept of the present application, and all of them should be regarded as falling within the protection scope of the present application.

Claims

1. An electrolyte for selective electrodeposition of copper-based array structures, characterized in that: The mixture comprises an aqueous phase and an oil phase. The aqueous phase contains 0.1-0.5 mol / L copper sulfate, 0.01-0.05 mol / L copper chloride, 2-9 μmol / L nitrogen-containing heterocyclic surfactant, 0.1-1.0 mmol / L anionic surfactant, and an inorganic acid. The oil phase comprises a low-conductivity organic solvent with a conductivity of less than 10. -5 S / m, density is 0.75 g / cm³ 3 -1.25g / cm 3 The inorganic acid is sulfuric acid, nitric acid, or hydrochloric acid, and the pH value of the aqueous phase is 1-3.

2. The electrolyte for selective electrodeposition of copper-based array structures according to claim 1, characterized in that: The nitrogen-containing heterocyclic surfactant is benzimidazole or 2-mercaptobenzimidazole, the anionic surfactant is sodium dodecyl sulfate, and the low-conductivity organic solvent is one or a mixture of two or more of cyclohexane, paraffin oil, silane, bromobenzene, and chloroform.

3. The electrolyte for selective electrodeposition of copper-based array structures according to claim 1, characterized in that: The volume ratio of the oil phase to the water phase is 1 to 3:

1.

4. The electrolyte for selective electrodeposition of copper-based array structures according to claim 1, characterized in that: The inorganic acid is sulfuric acid, and the concentration of the sulfuric acid in the aqueous phase is 0.01-0.1 mol / L.

5. A method for fabricating a selectively electrodeposited copper-based array structure, characterized in that, include: Using the electrolyte for selective electrodeposition of copper-based array structures as described in any one of claims 1 to 4, the cathode is connected to the substrate, the anode is connected to an inert electrode, and an external DC power supply is applied. By adjusting the current density, copper pillars or copper dendrite arrays are selectively electrodeposited under template-free conditions. When the current density is 5-20 mA / cm², 2 When the current density is 25–50 mA / cm², a copper column array is formed; 2 At that time, a copper dendrite array is formed.

6. The method for fabricating a selectively electrodeposited copper-based array structure according to claim 5, characterized in that: The electrodeposition process involves a potential of -0.4 to -0.6 V vs. SCE, a deposition temperature of 25 ± 5 °C, and a deposition time of 5 to 30 min.

7. The application of the method for fabricating a selective electrodeposition copper-based array structure as described in claim 5 or 6, characterized in that: Used in electronic packaging interconnects.

8. An electronic packaging interconnection method, characterized in that: A copper-based array structure is prepared at the soldering site of the substrate. The components to be soldered are placed on top of the copper-based array structure. Then, hot pressing or cold pressing bonding is performed at 30-250℃ and 1-50 MPa to form a "mechanical interlocking-metallurgical bonding" composite interface. The copper dendrite array fills the gaps through flexible branch plastic deformation, and the copper pillar array achieves mechanical interlocking through top plastic deformation. The copper-based array structure includes at least one of a copper dendrite array and a copper pillar array. The copper dendrite array has a multi-level branching structure and a length of 100-500 μm. The copper pillar array grows perpendicular to the substrate and has a diameter of 5-10 μm and a height of 10-30 μm.

9. The electronic packaging interconnection method according to claim 8, characterized in that: An activator is coated on the surface of the copper-based array structure, and then hot-pressed and sintered in air. The sintering temperature is not higher than 200°C, the hot-pressing pressure is 5-50 MPa, and the hot-pressing time is 15-30 min. The activator is at least one of ethanol, formic acid, and rosin.

10. An electronic packaging interconnect structure, characterized in that: The invention includes a chip, a substrate, and a copper-based array bonding layer sandwiched between the two. The copper-based array bonding layer is a copper-based array structure prepared by the selective electrodeposition method for preparing a copper-based array structure as described in claim 5 or 6. The copper-based array structure includes at least one of a copper dendrite array and a copper pillar array. The copper dendrite array has a multi-level branching structure. The copper pillar array grows perpendicular to the substrate.

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