High-stability lead frame for integrated circuit packaging and preparation method thereof

Abstract

The invention relates to the technical field of lead frames, in particular to a high-stability lead frame for integrated circuit packaging and a preparation method of the high-stability lead frame. The preparation method comprises the following steps: mixing graphene oxide, absolute ethyl alcohol, deionized water and modified POSS (Polyhedral Oligomeric Silsesquioxane), and stirring for reaction to obtain the reinforcing filler. Adding eugenol, epoxy chloropropane and bis (3-mercaptopropionic acid) glycol, and reacting to obtain an intermediate product; and mixing the intermediate product with the composite heat-conducting filler, and stirring for reaction to obtain the epoxidized composite heat-conducting filler. And mixing epoxy resin, the epoxidized composite heat-conducting filler, a diluent, an auxiliary agent, a reinforcing filler and a polyether amine curing agent to obtain the epoxy coating. And washing and drying the lead frame, coating the lead frame with an epoxy coating, and curing to form a high-stability coating, thereby obtaining the high-stability lead frame. The high-stability lead frame prepared by the invention has excellent corrosion resistance and thermal conductivity, so that the high-stability lead frame has a wide application prospect in the technical field of lead frames.

Description

Technical Field

[0001] This invention relates to the field of lead frame technology, specifically a high-stability lead frame for integrated circuit packaging and its fabrication method. Background Technology

[0002] In this era of rapid technological advancement, lead frames for integrated circuit packaging hold immeasurable value. In the miniaturization of electronic devices, lead frames, with their sophisticated design and manufacturing processes, enable high-density pin layouts, tightly connecting integrated circuit chips to external circuits and completing complex electrical transmissions within a limited space, providing strong support for the miniaturization of electronic devices. However, in environments with high temperatures, high humidity, or the presence of corrosive chemicals, lead frames are highly susceptible to corrosion. Once corrosion occurs, it can easily lead to lead breakage, interrupting signal transmission between the chip and external circuits, and ultimately causing the entire electronic device to malfunction. Furthermore, corrosion products can affect the normal operating environment of the chip, accelerating its aging and damage. Therefore, it is necessary to improve the corrosion resistance of lead frames to ensure their long-term stable operation in harsh environments and extend the lifespan of electronic devices.

[0003] Furthermore, as the performance of integrated circuit chips continues to improve, the amount of heat they generate during operation also increases. If this heat cannot be dissipated in time, the chip temperature will continue to rise. Excessively high temperatures can severely affect the chip's performance and stability, leading to decreased processing speed, data processing errors, and even serious failures such as thermal breakdown. Therefore, the lead frame, as part of the heat dissipation channel between the chip and the outside world, needs to have good thermal conductivity to quickly conduct the heat generated by the chip away, reduce the chip's operating temperature, and decrease the probability of performance degradation and failure due to overheating.

[0004] To overcome the shortcomings of the prior art, the present invention provides a high-stability lead frame for integrated circuit packaging and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a high-stability lead frame for integrated circuit packaging and its fabrication method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a high-stability lead frame for integrated circuit packaging includes the following steps: premixing epoxy resin, epoxy composite thermally conductive filler, diluent and additives, then adding reinforcing filler and polyetheramine curing agent for secondary mixing to obtain an epoxy coating; washing and drying the lead frame and coating it with the epoxy coating, and curing it to form a high-stability coating to obtain a high-stability lead frame.

[0007] The optimal premixing parameters are: mixing at 35-40℃ for 25-30 min, and secondary mixing parameters are: mixing at 20-35℃ for 10-15 min.

[0008] In a more optimized manner, the content of each component in the epoxy coating is as follows: by mass parts, 90-100 parts epoxy resin, 20-30 parts epoxy composite thermally conductive filler, 5-10 parts diluent, 1-2 parts additives, 8-12 parts reinforcing filler, and 20-30 parts polyetheramine curing agent; wherein the diluent is ethylene glycol diglycidyl ether; and the additive is a defoamer.

[0009] A more optimized preparation process for reinforcing fillers is as follows: Step S1: Mix methanol and 36-38 wt% hydrochloric acid by stirring. While stirring, add γ-mercaptopropyltrimethoxysilane and circulate the mixture under condensation at 90-95°C for 60-70 h. After the reaction is complete, allow the mixture to stand, wash, rotary evaporate, remove water, and recrystallize to obtain mercapto-POSS. Step S2: Add polyvinylpyrrolidone to ethanol, stir evenly, and then add mercapto-POSS and 3-isocyanate-propyltrimethoxysilane in sequence. Stir and react at 25-30℃ for 8-10 hours. After the reaction is completed, centrifuge, wash and dry to obtain modified POSS. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and then ultrasonically disperse them evenly. Add sodium hydroxide solution to adjust the pH of the solution to 10.0-10.5. Stir and react at 60-65℃ for 12-14 hours. After the reaction is completed, wash, filter, and dry to obtain the reinforced filler.

[0010] In a more optimized manner, in step S1, the reaction volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane is 20:2:(1.0-1.2); in step S2, the reaction mass ratio of mercapto-POSS and 3-isocyanate-propyltrimethoxysilane is 1:(1.7-1.9).

[0011] In a more optimized manner, in step S3, the mass-to-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is (1.5-2.0) g: 120 mL: 40 mL: (5-6) g.

[0012] A more optimized preparation process for epoxidized composite thermally conductive fillers is as follows: Step S1: Mix eugenol and deionized water, stir until homogeneous, then add epichlorohydrin, followed by tetrabutylammonium bromide. Stir at 25-30℃ for 1.0-1.5h. After stirring, raise the temperature to 75-80℃ and slowly add 25-30wt% sodium hydroxide solution. Continue the reaction for 2-3h after the addition is complete. After the reaction is complete, rotary evaporate to obtain epoxidized eugenol. Then mix bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol, stir until homogeneous, then add photoinitiator 1173. React under ultraviolet light for 4-6h to obtain the intermediate product. Step S2: Add Ti3AlC2 to 12-13 mol / L hydrofluoric acid and pre-react at 0-2℃ for 15-20 min, then react at 25-30℃ for 20-25 h. After the reaction, centrifuge, wash, and freeze-dry to obtain MXene material. Then add MXene material to deionized water and ultrasonically disperse for 40-60 min. Then slowly add silver nitrate aqueous solution and stir at 0-2℃ for 2-3 h. After stirring, filter, wash, and dry to obtain composite thermally conductive filler. Step S3: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 20-30 min, then add the intermediate product, and stir and react at 25-30℃ for 8-10 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler.

[0013] In a more optimized manner, in step S1, the molar ratio of eugenol to epichlorohydrin is (1.1-1.2):1; and the molar ratio of bis(3-mercaptopropionic acid) glycol to epoxidized eugenol is 1:(0.95-1.0).

[0014] In a more optimized manner, in step S2, the mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid is 1 g: (17-20) mL; the reaction mass ratio of MXene material to silver nitrate is 30: (1.5-1.7); and in step S3, the reaction mass ratio of composite thermally conductive filler to intermediate product is 1: (2-3).

[0015] The beneficial effects of this invention are: The key feature of this invention is the hydrolysis-condensation reaction involving the addition of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane to obtain mercapto-POSS. The cage-like structure of POSS possesses a certain rigidity and stability, enabling it to form a physical barrier within the material, preventing the penetration and diffusion of corrosive media and thus protecting the matrix material from corrosion. Mercapto-POSS is then mixed with 3-isocyanate-propyltrimethoxysilane, using polyvinylpyrrolidone as a dispersant, to obtain modified POSS. This step introduces new functional groups and chemical bonds, further enhancing intermolecular interactions and cross-linking. This cross-linked structure improves the material's density, reduces the penetration channels of corrosive media, and thus enhances corrosion resistance.

[0016] Next, graphene oxide, anhydrous ethanol, deionized water, and modified POSS are mixed. The trimethoxysilyl groups in the modified POSS undergo hydrolysis to generate silanol groups, which then condense with the hydroxyl groups on the surface of graphene oxide to form covalent bonds, resulting in a reinforced filler. Graphene oxide possesses excellent barrier properties; its layered structure can form tortuous channels within the material, significantly extending the diffusion path of corrosive media. When covalently bonded with modified POSS, the two work synergistically to further enhance the material's shielding performance.

[0017] The key feature of this invention is that a nucleophilic substitution reaction is initiated by adding eugenol and epichlorohydrin to obtain epoxidized eugenol. Then, epoxidized eugenol is mixed with ethylene glycol bis(3-mercaptopropionic acid) to undergo a mercapto-ene click reaction, yielding an intermediate product. This step, by setting the molar ratio of ethylene glycol bis(3-mercaptopropionic acid) to epoxidized eugenol to 1:0.97, ensures that a certain amount of mercapto groups remain in the intermediate product. Finally, Ti3AlC2, hydrofluoric acid, and silver nitrate are added to generate silver nanoparticles on MXene material through in-situ reduction, thus preparing a composite thermally conductive filler.

[0018] The unique two-dimensional layered structure of MXene provides excellent phonon transport channels, enabling efficient heat transfer between layers. Silver, an excellent thermally conductive metal, with silver nanoparticles uniformly distributed on the surface of MXene, fills defects and gaps between the layers, reducing phonon scattering. Furthermore, the silver nanoparticles form a good interfacial contact with MXene, promoting heat transfer and further improving the overall thermal conductivity of the composite thermally conductive filler. A thiol-containing intermediate product is then mixed with the composite thermally conductive filler for a coordination reaction, yielding an epoxidized composite thermally conductive filler. This chemical bonding creates a continuous thermally conductive network structure, reducing obstacles to heat transfer and further enhancing the material's thermal conductivity. Simultaneously, the introduction of epoxy groups into the composite thermally conductive filler promotes effective compatibility between the epoxidized composite thermally conductive filler and the main resin.

[0019] The present invention is characterized in that, finally, epoxy resin, epoxy composite thermally conductive filler, diluent and additives are premixed, and then reinforcing filler and polyetheramine curing agent are added for secondary mixing to obtain epoxy coating; after washing and drying, the lead frame is coated with epoxy coating, and after curing, a high-stability coating is formed to obtain a high-stability lead frame.

[0020] During premixing, stirring ensures the epoxy composite thermally conductive filler is fully dispersed in the epoxy resin. The epoxy groups on the surface of the filler have good compatibility with the epoxy resin and can be uniformly distributed within the epoxy resin matrix, preventing filler agglomeration. Simultaneously, the uniformly dispersed epoxy composite thermally conductive filler forms a more continuous and complete thermally conductive network, improving the coating's thermal conductivity. In the secondary mixing process, reinforcing fillers and a polyetheramine curing agent are added. The amino groups in the polyetheramine curing agent undergo ring-opening addition reactions with the epoxy groups in the epoxy resin and the epoxy composite thermally conductive filler, forming a three-dimensional network structure. This cross-linked structure gives the coating high hardness and strength, resisting external physical and chemical corrosion. Furthermore, the cross-linked structure further improves the coating's density, reducing the penetration channels of corrosive media and thus enhancing the coating's corrosion resistance. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only 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.

[0022] Raw material source: Polyvinylpyrrolidone (PVP), provided by Shanghai Zhenlishi Network Technology Co., Ltd., model Sokalan K30 P; Graphene oxide, provided by Zhejiang Zhitai Nano-Micro New Materials Co., Ltd., with an average thickness of 2nm; Ti3AlC2, provided by Foshan Xinxi Technology Co., Ltd., specification 200 mesh; Epoxy resin, provided by Jinan Chenghao Chemical Co., Ltd., grade E-44; Defoamer, provided by Shenzhen Longdi Chemical Co., Ltd., model BYK-A535; Polyetheramine curing agent, provided by Guangzhou Taili Chemical Co., Ltd., model T403; Lead frame, provided by Shanghai Xinyue Metal Products Co., Ltd., material C19400 copper alloy; by weight, one part is 1g.

[0023] Example 1: Step S1: Methanol and 37wt% hydrochloric acid were stirred and mixed. γ-mercaptopropyltrimethoxysilane was added while stirring. The mixture was cyclically condensed at 95°C for 70 hours. After the reaction was completed, the mixture was allowed to stand, washed, rotary evaporated, dehydrated, and recrystallized to obtain mercapto-POSS. The volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane was 20:2:1.1. Step S2: Polyvinylpyrrolidone was added to ethanol and stirred until homogeneous. Then, mercapto-POSS and 3-isocyanate-propyltrimethoxysilane were added sequentially. The mixture was stirred at 30°C for 10 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified POSS. The mass ratio of mercapto-POSS to 3-isocyanate-propyltrimethoxysilane was 1:1.8. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and ultrasonically disperse them evenly. Then add sodium hydroxide solution to adjust the pH of the solution to 10.5. Stir and react at 65℃ for 14 hours. After the reaction is completed, wash, filter, and dry to obtain the reinforced filler. The mass-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is 1.6g:120mL:40mL:5.5g. Step S4: Eugenol and deionized water were mixed and stirred evenly. Epichlorohydrin was then added, followed by tetrabutylammonium bromide. The mixture was stirred at 30°C for 1.5 hours. After stirring, the temperature was raised to 80°C and 27wt% sodium hydroxide solution was slowly added dropwise. After the addition was complete, the reaction continued for 3 hours. After the reaction was completed, epoxidized eugenol was obtained by rotary evaporation. Then, bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol were mixed and stirred evenly. Photoinitiator 1173 was added, and the mixture was reacted under ultraviolet light for 6 hours to obtain the intermediate product. The molar ratio of eugenol to epichlorohydrin was 1.15:1; the molar ratio of bis(3-mercaptopropionic acid) ethylene glycol to epoxidized eugenol was 1:0.97. Step S5: Ti3AlC2 was added to 12.5 mol / L hydrofluoric acid and pre-reacted at 2℃ for 20 min, then reacted at 30℃ for 25 h. After the reaction, the mixture was centrifuged, washed, and freeze-dried to obtain MXene material. The MXene material was then added to deionized water and ultrasonically dispersed for 60 min. Silver nitrate aqueous solution was then slowly added, and the mixture was stirred at 2℃ for 3 h. After stirring, the mixture was filtered, washed, and dried to obtain the composite thermally conductive filler. The mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid was 1 g:18 mL; the mass ratio of MXene material to silver nitrate was 30:1.6. Step S6: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 30 min, then add the intermediate product, and stir and react at 30℃ for 10 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler; the reaction mass ratio of composite thermally conductive filler to intermediate product is 1:2.5. Step S7: Premix 90g epoxy resin, 20g epoxy composite thermally conductive filler, 5g ethylene glycol diglycidyl ether and 1g defoamer, then add 8g reinforcing filler and 20g polyetheramine curing agent for secondary mixing to obtain epoxy coating; after washing and drying the lead frame, coat it with epoxy coating, and after curing, form a high-stability coating to obtain a high-stability lead frame; premixing parameters: mix at 40℃ for 30min, secondary mixing parameters: mix at 35℃ for 15min.

[0024] Example 2: Step S1: Methanol and 37wt% hydrochloric acid were stirred and mixed. γ-mercaptopropyltrimethoxysilane was added while stirring. The mixture was cyclically condensed at 93°C for 65 hours. After the reaction was completed, the mixture was allowed to stand, washed, rotary evaporated, dehydrated, and recrystallized to obtain mercapto-POSS. The volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane was 20:2:1.1. Step S2: Polyvinylpyrrolidone was added to ethanol and stirred until homogeneous. Then, mercapto-POSS and 3-isocyanate-propyltrimethoxysilane were added sequentially. The mixture was stirred at 27°C for 9 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified POSS. The mass ratio of mercapto-POSS to 3-isocyanate-propyltrimethoxysilane was 1:1.8. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and ultrasonically disperse them evenly. Then add sodium hydroxide solution to adjust the pH of the solution to 10.2. Stir and react at 62℃ for 13 hours. After the reaction is complete, wash, filter, and dry to obtain the reinforced filler. The mass-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is 1.6g:120mL:40mL:5.5g. Step S4: Eugenol and deionized water were mixed and stirred evenly. Epichlorohydrin was then added, followed by tetrabutylammonium bromide. The mixture was stirred at 27°C for 1.3 hours. After stirring, the temperature was raised to 77°C and 27wt% sodium hydroxide solution was slowly added dropwise. After the addition was complete, the reaction continued for 2.5 hours. After the reaction was completed, epoxidized eugenol was obtained by rotary evaporation. Then, bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol were mixed and stirred evenly. Photoinitiator 1173 was added, and the mixture was reacted under ultraviolet light for 5 hours to obtain the intermediate product. The molar ratio of eugenol to epichlorohydrin was 1.15:1; the molar ratio of bis(3-mercaptopropionic acid) ethylene glycol to epoxidized eugenol was 1:0.97. Step S5: Ti3AlC2 was added to 12.5 mol / L hydrofluoric acid and pre-reacted at 1℃ for 17 min, then reacted at 27℃ for 23 h. After the reaction, the mixture was centrifuged, washed, and freeze-dried to obtain MXene material. The MXene material was then added to deionized water and ultrasonically dispersed for 50 min. Silver nitrate aqueous solution was then slowly added, and the mixture was stirred at 1℃ for 2.5 h. After stirring, the mixture was filtered, washed, and dried to obtain the composite thermally conductive filler. The mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid was 1 g:18 mL; the mass ratio of MXene material to silver nitrate was 30:1.6. Step S6: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 25 min, then add the intermediate product, and stir and react at 27°C for 9 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler; the reaction mass ratio of composite thermally conductive filler to intermediate product is 1:2.5. Step S7: Premix 90g epoxy resin, 20g epoxy composite thermally conductive filler, 5g ethylene glycol diglycidyl ether and 1g defoamer, then add 8g reinforcing filler and 20g polyetheramine curing agent for secondary mixing to obtain epoxy coating; after washing and drying the lead frame, coat it with epoxy coating, and after curing, form a high-stability coating to obtain a high-stability lead frame; premixing parameters: mix at 37℃ for 27min, secondary mixing parameters: mix at 27℃ for 12min.

[0025] Example 3: Step S1: Methanol and 37wt% hydrochloric acid were stirred and mixed, and γ-mercaptopropyltrimethoxysilane was added while stirring. The mixture was cyclically condensed at 90°C for 60 hours. After the reaction was completed, the mixture was allowed to stand, washed, rotary evaporated, dehydrated, and recrystallized to obtain mercapto-POSS. The reaction volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane was 20:2:1.1. Step S2: Polyvinylpyrrolidone was added to ethanol and stirred until homogeneous. Then, mercapto-POSS and 3-isocyanate-propyltrimethoxysilane were added sequentially. The mixture was stirred at 25°C for 8 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified POSS. The mass ratio of mercapto-POSS to 3-isocyanate-propyltrimethoxysilane was 1:1.8. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and ultrasonically disperse them evenly. Then add sodium hydroxide solution to adjust the pH of the solution to 10.0. Stir and react at 60℃ for 12 hours. After the reaction is complete, wash, filter, and dry to obtain the reinforced filler. The mass-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is 1.6g:120mL:40mL:5.5g. Step S4: Eugenol and deionized water were mixed and stirred evenly. Epichlorohydrin was then added, followed by tetrabutylammonium bromide. The mixture was stirred at 25°C for 1.0 h. After stirring, the temperature was raised to 75°C and 27 wt% sodium hydroxide solution was slowly added dropwise. After the addition was complete, the reaction continued for 2 h. After the reaction was completed, epoxidized eugenol was obtained by rotary evaporation. Then, bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol were mixed and stirred evenly. Photoinitiator 1173 was added, and the mixture was reacted under ultraviolet light for 4 h to obtain the intermediate product. The molar ratio of eugenol to epichlorohydrin was 1.15:1; the molar ratio of bis(3-mercaptopropionic acid) ethylene glycol to epoxidized eugenol was 1:0.97. Step S5: Ti3AlC2 was added to 12.5 mol / L hydrofluoric acid and pre-reacted at 0℃ for 15 min, then reacted at 25℃ for 20 h. After the reaction, the mixture was centrifuged, washed, and freeze-dried to obtain MXene material. The MXene material was then added to deionized water and ultrasonically dispersed for 40 min. Silver nitrate aqueous solution was then slowly added, and the mixture was stirred at 0℃ for 2 h. After stirring, the mixture was filtered, washed, and dried to obtain the composite thermally conductive filler. The mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid was 1 g:18 mL; the mass ratio of MXene material to silver nitrate was 30:1.6. Step S6: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 20 min, then add the intermediate product, and stir and react at 25 °C for 8 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler; the reaction mass ratio of composite thermally conductive filler to intermediate product is 1:2.5. Step S7: Premix 90g epoxy resin, 20g epoxy composite thermally conductive filler, 5g ethylene glycol diglycidyl ether and 1g defoamer, then add 8g reinforcing filler and 20g polyetheramine curing agent for secondary mixing to obtain epoxy coating; after washing and drying the lead frame, coat it with epoxy coating, and after curing, form a high-stability coating to obtain a high-stability lead frame; premixing parameters: mix at 35℃ for 25min, secondary mixing parameters: mix at 20℃ for 10min.

[0026] Comparative Example 1: The epoxidized composite thermally conductive filler was removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Methanol and 37wt% hydrochloric acid were stirred and mixed. γ-mercaptopropyltrimethoxysilane was added while stirring. The mixture was cyclically condensed at 95°C for 70 hours. After the reaction was completed, the mixture was allowed to stand, washed, rotary evaporated, dehydrated, and recrystallized to obtain mercapto-POSS. The reaction volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane was 20:2:1.1. Step S2: Polyvinylpyrrolidone was added to ethanol and stirred until homogeneous. Then, mercapto-POSS and 3-isocyanate-propyltrimethoxysilane were added sequentially. The mixture was stirred at 30°C for 10 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified POSS. The mass ratio of mercapto-POSS to 3-isocyanate-propyltrimethoxysilane was 1:1.8. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and ultrasonically disperse them evenly. Then add sodium hydroxide solution to adjust the pH of the solution to 10.5. Stir and react at 65℃ for 14 hours. After the reaction is completed, wash, filter, and dry to obtain the reinforced filler. The mass-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is 1.6g:120mL:40mL:5.5g. Step S4: Premix 90g epoxy resin, 5g ethylene glycol diglycidyl ether and 1g defoamer, then add 8g reinforcing filler and 20g polyetheramine curing agent for secondary mixing to obtain epoxy coating; after washing and drying the lead frame, coat it with epoxy coating, and after curing, form a high-stability coating to obtain a high-stability lead frame; premixing parameters: mix at 40℃ for 30min, secondary mixing parameters: mix at 35℃ for 15min.

[0027] Comparative Example 2: The reinforcing filler was removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Eugenol and deionized water were mixed and stirred evenly, then epichlorohydrin was added, followed by tetrabutylammonium bromide. The mixture was stirred at 30°C for 1.5 h. After stirring, the temperature was raised to 80°C and 27 wt% sodium hydroxide solution was slowly added dropwise. After the addition was completed, the reaction continued for 3 h. After the reaction was completed, the product was obtained by rotary evaporation. Then, bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol were mixed and stirred evenly, and then photoinitiator 1173 was added. The mixture was reacted under ultraviolet light for 6 h to obtain an intermediate product. The molar ratio of eugenol to epichlorohydrin was 1.15:1; the molar ratio of bis(3-mercaptopropionic acid) ethylene glycol to epoxidized eugenol was 1:0.97. Step S2: Ti3AlC2 was added to 12.5 mol / L hydrofluoric acid and pre-reacted at 2℃ for 20 min, then reacted at 30℃ for 25 h. After the reaction, the mixture was centrifuged, washed, and freeze-dried to obtain MXene material. The MXene material was then added to deionized water and ultrasonically dispersed for 60 min. Silver nitrate aqueous solution was then slowly added, and the mixture was stirred at 2℃ for 3 h. After stirring, the mixture was filtered, washed, and dried to obtain the composite thermally conductive filler. The mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid was 1 g:18 mL; the mass-to-reaction ratio of MXene material to silver nitrate was 30:1.6. Step S3: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 30 min, then add the intermediate product, and stir and react at 30℃ for 10 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler; the reaction mass ratio of composite thermally conductive filler to intermediate product is 1:2.5. Step S4: Premix 90g of epoxy resin, 20g of epoxy composite thermally conductive filler, 5g of ethylene glycol diglycidyl ether and 1g of defoamer, then add 20g of polyetheramine curing agent for secondary mixing to obtain epoxy coating; after washing and drying the lead frame, coat it with epoxy coating, and after curing, form a high-stability coating to obtain a high-stability lead frame; premixing parameters: mix at 40℃ for 30min, secondary mixing parameters: mix at 35℃ for 15min.

[0028] Testing and experimentation: Corrosion resistance test: The high-stability lead frames prepared in Examples 1-2 of this invention were used as samples for testing. Accelerated salt spray corrosion tests were conducted using a neutral NaCl solution according to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test". The concentration of the NaCl solution was 50 g / L, and the test period was 50 h. The corrosion rate was calculated using the weight loss method, utilizing the mass of the substrate sample before and after neutral salt spray corrosion.

[0029] Thermal conductivity test: The epoxy coatings prepared in Examples 1-2 of this invention were placed in a mold and cured to test the thermal conductivity of the samples. The thermal conductivity of the samples was tested using a Hot Disk TPS 2500S thermal conductivity analyzer. The results are shown in the table below:

[0030] Conclusion: In Examples 1-3, the dosage remained unchanged, with only some reaction parameters modified. Experimental data showed no significant fluctuations in the performance of the samples.

[0031] Comparative Example 1: The epoxy composite thermally conductive filler was removed, and the rest was the same as in Example 1. The experimental data showed that the thermal conductivity was reduced to 0.59 W / m·K compared with Example 1. The reason for this is that the epoxy composite thermally conductive filler contains MXene thermally conductive material and silver thermally conductive material. The synergistic effect of the two can effectively improve the thermal conductivity of the material. Therefore, after removing it, the thermal conductivity was significantly reduced.

[0032] Comparative Example 2: The reinforcing filler was removed, and the rest was the same as in Example 1. Experimental data showed that, compared to Example 1, the corrosion rate increased to 2.881 g / (m²). 2 The reason for this is that the reinforcing filler contains graphene and POSS materials, which have excellent corrosion resistance. Therefore, removing them reduces corrosion resistance and increases the corrosion rate.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0034] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating a high-stability lead frame for integrated circuit packaging, characterized in that: Includes the following steps: Epoxy resin, epoxy composite thermally conductive filler, diluent and additives are premixed, and then reinforcing filler and polyetheramine curing agent are added for secondary mixing to obtain epoxy coating; After washing and drying, the lead frame is coated with epoxy paint and cured to form a highly stable coating, resulting in a highly stable lead frame.

2. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 1, characterized in that: Premixing parameters: mix at 35-40℃ for 25-30 min; secondary mixing parameters: mix at 20-35℃ for 10-15 min.

3. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 1, characterized in that: The epoxy coating contains the following components by weight: 90-100 parts epoxy resin, 20-30 parts epoxy composite thermally conductive filler, 5-10 parts diluent, 1-2 parts additives, 8-12 parts reinforcing filler, and 20-30 parts polyetheramine curing agent; the diluent is ethylene glycol diglycidyl ether; and the additive is a defoamer.

4. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 3, characterized in that: The preparation process of the reinforcing filler is as follows: Step S1: Mix methanol and 36-38 wt% hydrochloric acid by stirring. While stirring, add γ-mercaptopropyltrimethoxysilane and circulate the mixture under condensation at 90-95°C for 60-70 h. After the reaction is complete, allow the mixture to stand, wash, rotary evaporate, remove water, and recrystallize to obtain mercapto-POSS. Step S2: Add polyvinylpyrrolidone to ethanol, stir evenly, and then add mercapto-POSS and 3-isocyanate-propyltrimethoxysilane in sequence. Stir and react at 25-30℃ for 8-10 hours. After the reaction is completed, centrifuge, wash and dry to obtain modified POSS. Step S3: Mix graphene oxide, anhydrous ethanol, deionized water, and modified POSS, and then ultrasonically disperse them evenly. Add sodium hydroxide solution to adjust the pH of the solution to 10.0-10.

5. Stir and react at 60-65℃ for 12-14 hours. After the reaction is completed, wash, filter, and dry to obtain the reinforced filler.

5. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 4, characterized in that: In step S1, the reaction volume ratio of methanol, hydrochloric acid, and γ-mercaptopropyltrimethoxysilane is 20:2:(1.0-1.2); in step S2, the reaction mass ratio of mercapto-POSS and 3-isocyanate-propyltrimethoxysilane is 1:(1.7-1.9).

6. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 4, characterized in that: In step S3, the mass-to-volume ratio of graphene oxide, anhydrous ethanol, deionized water, and modified POSS is (1.5-2.0) g: 120 mL: 40 mL: (5-6) g.

7. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 3, characterized in that: The preparation process of the epoxidized composite thermally conductive filler is as follows: Step S1: Mix eugenol and deionized water, stir until homogeneous, then add epichlorohydrin, followed by tetrabutylammonium bromide. Stir at 25-30℃ for 1.0-1.5h. After stirring, raise the temperature to 75-80℃ and slowly add 25-30wt% sodium hydroxide solution. Continue the reaction for 2-3h after the addition is complete. After the reaction is complete, rotary evaporate to obtain epoxidized eugenol. Then mix bis(3-mercaptopropionic acid) ethylene glycol and epoxidized eugenol, stir until homogeneous, then add photoinitiator 1173. React under ultraviolet light for 4-6h to obtain the intermediate product. Step S2: Add Ti3AlC2 to 12-13 mol / L hydrofluoric acid and pre-react at 0-2℃ for 15-20 min, then react at 25-30℃ for 20-25 h. After the reaction, centrifuge, wash, and freeze-dry to obtain MXene material. Then add MXene material to deionized water and ultrasonically disperse for 40-60 min. Then slowly add silver nitrate aqueous solution and stir at 0-2℃ for 2-3 h. After stirring, filter, wash, and dry to obtain composite thermally conductive filler. Step S3: Add the composite thermally conductive filler to ethanol, ultrasonically disperse for 20-30 min, then add the intermediate product, and stir and react at 25-30℃ for 8-10 h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain the epoxidized composite thermally conductive filler.

8. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 7, characterized in that: In step S1, the molar ratio of eugenol to epichlorohydrin is (1.1-1.2):1; the molar ratio of bis(3-mercaptopropionic acid) glycol to epoxidized eugenol is 1:(0.95-1.0).

9. The method for fabricating a high-stability lead frame for integrated circuit packaging according to claim 7, characterized in that: In step S2, the mass-to-volume ratio of Ti3AlC2 to hydrofluoric acid is 1 g: (17-20) mL; the reaction mass ratio of MXene material to silver nitrate is 30: (1.5-1.7); in step S3, the reaction mass ratio of composite thermally conductive filler to intermediate product is 1: (2-3).

10. A high-stability lead frame for integrated circuit packaging, characterized in that, Prepared by the preparation method according to any one of claims 1-9.

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