Epoxy adhesive for semiconductor chip packaging and preparation process thereof

Abstract

This invention relates to the field of epoxy adhesive technology, and discloses an epoxy adhesive for semiconductor chip packaging and its preparation process; including the following steps: Step 1: Epoxy resin and 3-(perfluorohexyl)epoxypropane are added to ethanol and mixed evenly, then 2-imidazolium-1-ethylamine is added, and the mixture is reacted at 50~60℃ for 4~6 hours to obtain modified epoxy resin; Step 2: Modified epoxy resin, modified polyurethane, defoamer, and diluent are vacuumed and stirred at 800~1200 rpm / min for 40~50 minutes, then nano zinc oxide and curing agent are added sequentially, and the stirring speed is reduced to 200~400 rpm / min for 1~2 hours to obtain epoxy adhesive.

Description

Technical Field

[0001] This invention relates to the field of epoxy adhesive technology, specifically an epoxy adhesive for semiconductor chip packaging and its preparation process. Background Technology

[0002] With the rapid development of semiconductor technology, the packaging process of semiconductor chips has become increasingly critical. Semiconductor chips play an important role in electronic devices, performing core computing and control functions, and their performance directly affects the quality and lifespan of the entire electronic device. Among these, chip packaging is a crucial step in protecting the chip, achieving electrical connections, and providing physical support, and it places high demands on packaging materials.

[0003] Epoxy adhesive has become a commonly used material in the field of semiconductor chip packaging. Epoxy resin itself is a thermosetting polymer that can form a substance with high strength, corrosion resistance and excellent insulation properties after curing. Its strong adhesive force can firmly bond the chip to the carrier material, ensuring stable and durable electrical connection. At the same time, the curing process of epoxy adhesive is relatively simple, providing great flexibility for the packaging process.

[0004] However, there are still some problems with existing epoxy adhesives for semiconductor chip packaging that need to be improved; (1) In terms of thermal conductivity, epoxy adhesives need to have good heat dissipation capabilities to prevent chip performance degradation due to overheating, but some epoxy adhesives have insufficient thermal conductivity and cannot meet the growing heat dissipation requirements of high-power chips; (2) In terms of chemical stability, as the environment in which electronic devices are used becomes more complex, epoxy adhesives need to have stronger stability to resist the erosion of moisture, pollutants and other chemicals, and ensure that chips work normally in various harsh environments.

[0005] In summary, the preparation of an epoxy adhesive for semiconductor chip packaging is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide an epoxy adhesive for semiconductor chip packaging and its preparation process, so as to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A process for preparing epoxy adhesive for semiconductor chip packaging includes the following steps:

[0009] Step 1: Add epoxy resin and 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 2-imidazolium-1-ethylamine and react at 50~60℃ for 4~6 hours to obtain modified epoxy resin.

[0010] Step 2: Vacuum the modified epoxy resin, modified polyurethane, defoamer, and diluent, and stir at 800~1200 rpm / min for 40~50 minutes. Then add nano zinc oxide and curing agent in sequence, reduce the speed to 200~400 rpm / min and stir for 1~2 hours to obtain epoxy adhesive.

[0011] In a more optimized form, the raw materials for the modified epoxy resin include the following components: by mass, 50-60 parts epoxy resin, 10-12 parts 3-(perfluorohexyl)epoxypropane, and 6-6.5 parts 2-imidazol-1-ethylamine.

[0012] In a more optimized form, the raw materials of the epoxy adhesive include the following components: by weight, 60-75 parts modified epoxy resin, 20-25 parts modified polyurethane, 10-15 parts nano zinc oxide, 3-6 parts defoamer, 2-4 parts curing agent, and 8-12 parts diluent.

[0013] A more optimized method for preparing the modified polyurethane is as follows: (1) 1,12-dodecanediol is added to dichloromethane, and under a nitrogen atmosphere and ice-water bath conditions, epoxidized silica and triethylamine are added and mixed evenly for 10-12 hours. Deionized water is added to terminate the reaction, and the pH value is adjusted to neutral. The mixture is filtered, washed, and dried to obtain modified silica. (2) Modified silica is added to DMF and ultrasonically dispersed to obtain a modified silica mixture. Toluene-2,6-diisocyanate is stirred at 50-60°C for 1-2 hours, nitrogen is introduced, and polyether polyol and modified silica mixture are added. The temperature is raised to 80-85°C and the reaction is carried out for 2-2.5 hours. 1H-imidazolium-4,5-diethanol and catalyst are added, and the reaction is continued for 1-2 hours. The mixture is dried to obtain modified polyurethane.

[0014] In a more optimized form, the modified silica raw material comprises the following components: by mass parts, 4-6 parts of epoxidized silica, 1.5-2.7 parts of 1,12-dodecanediol, and 0.17-0.3 parts of triethylamine.

[0015] In a more optimized form, the raw materials for the modified polyurethane include the following components: by weight parts, 6-9 parts toluene-2,6-diisocyanate, 2-3 parts polyether polyol, 5-7 parts modified silica mixture, 1.7-2.5 parts 1H-imidazol-4,5-diethanol, and 0.02-0.03 parts catalyst; wherein the modified silica accounts for 10-20 wt% of the modified silica mixture.

[0016] In a more optimized configuration, the curing agent is 4,4'-diaminodiphenyl disulfide; the defoamer is one of mineral oil defoamer and polyether defoamer; and the diluent includes one or both of ethylene glycol dimethyl ether and epoxy propylene ether.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This method involves uniformly mixing 3-(perfluorohexyl)propane oxide with epoxy resin, then reacting it with 2-imidazolium-1-ethylamine under certain conditions to obtain modified epoxy resin; then, the modified epoxy resin, modified polyurethane, diluent, defoamer, nano zinc oxide, and curing agent are mixed to prepare epoxy adhesive.

[0019] Among them, the perfluorohexyl group in 3-(perfluorohexyl)propene oxide is a relatively flexible segment that can provide excellent water repellency and high temperature resistance. It can improve the hydrophobicity of epoxy resin, making it difficult for water to penetrate into the material and reducing the probability of epoxy resin damage in hydrothermal environments. At the same time, it can also increase the internal crosslinking density and intermolecular forces of epoxy resin, thereby enhancing its adhesion to semiconductor chips and improving the brittleness of epoxy resin after curing.

[0020] In this method, 1,12-dodecanediol is reacted with epoxide silica under certain conditions to obtain modified silica. Then, modified silica, polyether polyol, and toluene-2,6-diisocyanate are used to prepare modified polyurethane. Among them, polyether polyol can improve the flexibility, elasticity, and weather resistance of polyurethane. 1,12-dodecanediol, through its long-chain alkyl groups, modifies the surface of epoxide silica, which can better match the other components in the polyurethane system, improve dispersibility and thermal stability, and effectively prevent moisture penetration. This can improve the thermal conductivity and mechanical properties of epoxy adhesive, and on the other hand, reduce the curing shrinkage rate.

[0021] To improve the interfacial compatibility between polyurethane and epoxy resin, the proposed method introduces compounds containing imidazole groups into both the epoxy resin and polyurethane. These modified imidazole groups can coordinate with zinc ions on nano-zinc oxide, enhancing the thermal stability of the epoxy adhesive and synergistically improving thermal conductivity with the nano-zinc oxide. Furthermore, this improves the dispersibility of the nano-zinc oxide, further enhancing the interfacial compatibility between the polyurethane and epoxy resin, as well as the tightness of the molecular structures, thereby improving the mechanical properties and adhesion of the epoxy adhesive. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] In the following specific embodiments, "parts" refers to parts by weight. In this embodiment, it should be noted that there are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: bisphenol A type epoxy resin, catalog number 15507, purchased from Jiangsu Congzhong Chemical Co., Ltd.; 3-(perfluorohexyl)epoxypropane, CAS number 38565-52-5; 2-imidazolium-1-ethylamine, CAS number 5739-10-6; 1,12-dodecanediol, CAS number 5675-51-4; triethylamine, CAS number 121-44-8; toluene-2,6-diisocyanate, CAS number 91-08-7; polyether polyol, catalog number YK0528, purchased from Hubei Yongkuo Technology Co., Ltd.; 1H-imidazolium... The CAS number for -4,5-dimethylethanol is 33457-48-6; the product number for polyether defoamer (GPE, defoamer) is 1, purchased from Lianyungang Haiheng Biochemical Technology Co., Ltd.; the CAS number for ethylene glycol diglycidyl ether (diluent) is 2224-15-9; the CAS number for 4,4'-diaminodiphenyl disulfide (curing agent) is 722-27-0; the model number for nano silica is YM-SiO2-dw05, with a particle size of 100nm, purchased from Yumu (Ningbo) New Materials Co., Ltd.; the CAS number for KH560 (3-(2,3-epoxypropoxy)propyltrimethoxysilane) is 2530-83-8; the model number for nano zinc oxide is YM-ZnO-02, with a particle size of 50nm, purchased from Yumu (Ningbo) New Materials Co., Ltd.

[0024] The preparation method of epoxy silica is as follows: 0.7 parts of KH560 and 2.2 parts of nano silica are added to 10 parts of 65wt% ethanol aqueous solution to obtain mixture A and mixture B; mixture B is added to mixture A and reacted at 70℃ for 6 hours; filtered, washed and dried to obtain epoxy silica.

[0025] Example 1: A process for preparing epoxy adhesive for semiconductor chip packaging, comprising the following steps:

[0026] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 6.5 parts of 2-imidazol-1-ethylamine and react at 50°C for 5 hours to obtain modified epoxy resin.

[0027] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The temperature was raised to 82°C and the reaction was carried out for 2 hours. 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added and the reaction was continued for 1.5 hours. The mixture was dried to obtain modified polyurethane.

[0028] Step 2: Mix 60 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts defoamer (polyether defoamer), and 8 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then add 10 parts nano zinc oxide and 2 parts 4,4'-diaminodiphenyl disulfide (curing agent) in sequence, reduce the speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0029] Example 2: A process for preparing epoxy adhesive for semiconductor chip packaging, comprising the following steps:

[0030] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 6.5 parts of 2-imidazol-1-ethylamine and react at 50°C for 5 hours to obtain modified epoxy resin.

[0031] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The temperature was raised to 82°C and the reaction was carried out for 2 hours. 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added and the reaction was continued for 1.5 hours. The mixture was dried to obtain modified polyurethane.

[0032] Step 2: Combine 70 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts defoamer (polyether defoamer), and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then, add 15 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) sequentially. Reduce the stirring speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0033] Example 3: A process for preparing epoxy adhesive for semiconductor chip packaging, comprising the following steps:

[0034] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 6.5 parts of 2-imidazol-1-ethylamine and react at 50°C for 5 hours to obtain modified epoxy resin.

[0035] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The temperature was raised to 82°C and the reaction was carried out for 2 hours. 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added and the reaction was continued for 1.5 hours. The mixture was dried to obtain modified polyurethane.

[0036] Step 2: Mix 75 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts polyether defoamer, and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then add 15 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) in sequence, reduce the speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0037] Comparative Example 1 is based on Example 2, but without the introduction of 3-(perfluorohexyl)propane oxide into the modified epoxy resin;

[0038] Step 1: (1) Add 60 parts of epoxy resin to ethanol and mix evenly, add 6.5 parts of 2-imidazol-1-ethylamine, and react at 50°C for 5 hours to obtain modified epoxy resin.

[0039] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The temperature was raised to 82°C and the reaction was carried out for 2 hours. 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added and the reaction was continued for 1.5 hours. The mixture was dried to obtain modified polyurethane.

[0040] Step 2: Mix 70 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts polyether defoamer, and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then add 15 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) in sequence. Reduce the speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0041] Comparative Example 2 is based on Example 2, but without introducing imidazole groups into the modified epoxy resin and modified polyurethane;

[0042] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly for 5 hours to obtain modified epoxy resin.

[0043] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The mixture was heated to 82°C and reacted for 2 hours. The mixture was dried to obtain modified polyurethane.

[0044] Step 2: Mix 70 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts polyether defoamer, and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then add 15 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) in sequence. Reduce the speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0045] Comparative Example 3 is based on Example 2, without modification of the epoxy resin;

[0046] Step 1: (1) Add 1.7 parts of 1,12-dodecanediol to dichloromethane. Under nitrogen atmosphere and ice-water bath conditions, add 6 parts of epoxidized silica and 0.25 parts of triethylamine. Mix evenly for 10 hours. Add deionized water to terminate the reaction and adjust the pH value to neutral. Filter, wash and dry to obtain modified silica; (2) Add modified silica to DMF and ultrasonically disperse to obtain a 15wt% modified silica mixture; Stir 8 parts of toluene-2,6-diisocyanate at 55℃ for 2 hours. Purge with nitrogen and add 2.5 parts of polyether polyol and 6 parts of modified silica mixture. Heat to 82℃ and react for 2 hours. Add 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst. Continue the reaction for 1.5 hours. Dry to obtain modified polyurethane;

[0047] Step 2: Combine 70 parts epoxy resin, 25 parts modified polyurethane, 3.5 parts polyether defoamer, and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then, add 15 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) sequentially. Reduce the stirring speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0048] Comparative Example 4 is based on Example 2, but without the addition of 1,12-dodecanediol;

[0049] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 6.5 parts of 2-imidazol-1-ethylamine and react at 50°C for 5 hours to obtain modified epoxy resin.

[0050] (2) Epoxy silica was added to DMF and ultrasonically dispersed to obtain a 15wt% epoxy silica mixture; 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours, nitrogen gas was introduced, 2.5 parts of polyether polyol were added, the temperature was raised to 82°C and reacted for 2 hours, 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added, and the reaction was continued for 1.5 hours. Under nitrogen protection, the temperature was lowered to 40°C, 6 parts of epoxy silica mixture were added, and the mixture was mixed evenly for 4 hours and dried to obtain modified polyurethane;

[0051] Step 2: Mix 70 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts polyether defoamer, and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Add 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) and reduce the speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0052] Comparative Example 5 is based on Example 2, but the amount of nano zinc oxide added is increased to 20 parts;

[0053] Step 1: (1) Add 60 parts of epoxy resin and 10 parts of 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 6.5 parts of 2-imidazol-1-ethylamine and react at 50°C for 5 hours to obtain modified epoxy resin.

[0054] (2) 1.7 parts of 1,12-dodecanediol were added to dichloromethane. Under a nitrogen atmosphere and an ice-water bath, 6 parts of epoxidized silica and 0.25 parts of triethylamine were added and mixed evenly for 10 hours. Deionized water was added to terminate the reaction, and the pH was adjusted to neutral. The mixture was filtered, washed, and dried to obtain modified silica. (3) Modified silica was added to DMF and ultrasonically dispersed to obtain a 15wt% modified silica mixture. 8 parts of toluene-2,6-diisocyanate were stirred at 55°C for 2 hours. Nitrogen gas was introduced, and 2.5 parts of polyether polyol and 6 parts of modified silica mixture were added. The temperature was raised to 82°C and the reaction was carried out for 2 hours. 1.7 parts of 1H-imidazol-4,5-diethanol and 0.022 parts of catalyst were added and the reaction was continued for 1.5 hours. The mixture was dried to obtain modified polyurethane.

[0055] Step 2: Combine 70 parts modified epoxy resin, 25 parts modified polyurethane, 3.5 parts defoamer (polyether defoamer), and 12 parts ethylene glycol diglycidyl ether (diluent) under vacuum and stir at 1200 rpm / min for 50 minutes. Then, add 20 parts nano zinc oxide and 4 parts 4,4'-diaminodiphenyl disulfide (curing agent) sequentially. Reduce the stirring speed to 300 rpm / min and stir for 2 hours to obtain epoxy adhesive.

[0056] Testing: Six epoxy resins prepared in Examples 1-3 and Comparative Examples 1-4 were taken and uniformly coated onto semiconductor chips, marked, and cured at 90°C for 2 hours. Then, they were boiled in a constant temperature water bath at 100°C for 72 hours, dried at 60°C, and then subjected to the following tests.

[0057] (1) According to GB / T7124-2008 standard, after the encapsulation of Examples 1-3 and Comparative Examples 1-5, the bonding strength after boiling in water was tested;

[0058] (2) The thermal conductivity of Examples 1-3 and Comparative Examples 1-5 after being packaged and boiled in water was tested according to ASTM D5470 standard.

[0059]

[0060] Table 1

[0061] Comparative Example 1, based on Example 2, did not introduce 3-(perfluorohexyl)epoxypropane into the modified epoxy resin; this resulted in a decrease in the hydrophobicity of the epoxy adhesive, thus leading to a decrease in the performance of the encapsulated semiconductor chip. Comparative Example 2, based on Example 2, did not introduce imidazole groups into the modified epoxy resin and modified polyurethane; this resulted in a decrease in the dispersibility of nano-zinc oxide and the interfacial compatibility between the epoxy resin and polyurethane, and the lack of metal coordination also led to a decrease in performance. Comparative Example 3, based on Example 2, did not modify the epoxy resin; this resulted in a decrease in the hydrophobicity of the epoxy adhesive, a decrease in the content of imidazole groups, a decrease in coordination performance, and ultimately a decrease in the performance of the cured epoxy adhesive. Comparative Example 4, based on Example 2, did not add 1,12-dodecanediol; this resulted in a decrease in hydrophobicity and a decrease in the compatibility of nano-silica in the polyurethane, thus leading to a decrease in the performance of the cured epoxy adhesive. Comparative Example 5, based on Example 2, increased the amount of nano-zinc oxide added; this resulted in a decrease in the dispersibility of nano-zinc oxide, thus leading to a decrease in the performance of the cured epoxy adhesive.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A process for preparing epoxy adhesive for semiconductor chip packaging, characterized in that: The following steps are included: Step 1: Add epoxy resin and 3-(perfluorohexyl)epoxypropane to ethanol and mix evenly. Add 2-imidazolium-1-ethylamine and react at 50~60℃ for 4~6 hours to obtain modified epoxy resin. Step 2: Vacuum the modified epoxy resin, modified polyurethane, defoamer, and diluent, and stir at 800-1200 rpm for 40-50 minutes. Then add nano zinc oxide and curing agent in sequence, reduce the speed to 200-400 rpm and stir for 1-2 hours to obtain epoxy adhesive. The modified polyurethane is prepared as follows: (1) 1,12-dodecanediol is added to dichloromethane, and under nitrogen atmosphere and ice-water bath conditions, epoxidized silica and triethylamine are added and mixed evenly for 10-12 hours. Deionized water is added to terminate the reaction, and the pH value is adjusted to neutral. The mixture is filtered, washed, and dried to obtain modified silica. (2) Modified silica is added to DMF and ultrasonically dispersed to obtain modified silica mixture. Toluene-2,6-diisocyanate is stirred at 50-60°C for 1-2 hours, nitrogen is introduced, polyether polyol and modified silica mixture are added, the temperature is raised to 80-85°C, and the reaction is carried out for 2-2.5 hours. 1H-imidazolium-4,5-diethanol and catalyst are added, and the reaction is continued for 1-2 hours. The mixture is dried to obtain modified polyurethane.

2. The preparation process of an epoxy adhesive for semiconductor chip packaging according to claim 1, characterized in that: The raw materials of the modified epoxy resin include the following components: by mass, 50-60 parts epoxy resin, 10-12 parts 3-(perfluorohexyl)epoxypropane, and 6-6.5 parts 2-imidazol-1-ethylamine.

3. The preparation process of an epoxy adhesive for semiconductor chip packaging according to claim 1, characterized in that: The raw materials of the epoxy adhesive include the following components: by mass parts, 60-75 parts modified epoxy resin, 20-25 parts modified polyurethane, 10-15 parts nano zinc oxide, 3-6 parts defoamer, 2-4 parts curing agent, and 8-12 parts diluent.

4. The preparation process of an epoxy adhesive for semiconductor chip packaging according to claim 1, characterized in that: The modified silica raw material comprises the following components: by mass, 4-6 parts of epoxidized silica, 1.5-2.7 parts of 1,12-dodecanediol, and 0.17-0.3 parts of triethylamine.

5. The preparation process of an epoxy adhesive for semiconductor chip packaging according to claim 1, characterized in that: The modified polyurethane raw materials include the following components: by weight parts, 6-9 parts toluene-2,6-diisocyanate, 2-3 parts polyether polyol, 5-7 parts modified silica mixture, 1.7-2.5 parts 1H-imidazol-4,5-diethanol, and 0.02-0.03 parts catalyst; the modified silica accounts for 10-20 wt% of the modified silica mixture.

6. The preparation process of an epoxy adhesive for semiconductor chip packaging according to claim 1, characterized in that: The curing agent is 4,4'-diaminodiphenyl disulfide; the defoamer is one of mineral oil defoamer and polyether defoamer; the diluent includes one or both of ethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether.

7. The epoxy adhesive is prepared according to the preparation process of the epoxy adhesive for semiconductor chip packaging according to any one of claims 1 to 6.

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