Method for improving performance of epoxy molding compound by using organic tin compound and application thereof

Abstract

The invention relates to a novel application, which utilizes the improvement of an organic tin compound in the aspect of an epoxy molding compound. Specifically, a proper amount of organic tin compound is added into the epoxy molding compound, so that the demolding property, the stability, the heat resistance and the corrosion resistance of the molding compound can be effectively improved, meanwhile, the formability and the curability in the plastic packaging process are optimized, and a more reliable and efficient solution is provided for semiconductor packaging.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor device packaging materials, and in particular relates to a method for improving the performance of epoxy molding compound by utilizing organic tin compounds and application thereof. Background Art

[0002] With the rapid development of microelectronics technology, the integration of semiconductor devices continues to increase. Epoxy molding compound, as the mainstream material for semiconductor packaging, has the advantages of small size, light weight, simple structure, and convenient process. However, with the continuous development of semiconductor technology, the requirements for packaging materials are also increasing. Traditional epoxy molding compounds have certain limitations in stability, heat resistance, and corrosion resistance. Especially in harsh environments such as high temperature and high humidity, their performance decays rapidly and it is difficult to meet the high performance requirements of modern semiconductor packaging. Therefore, the development of a new type of epoxy molding compound to improve its performance and meet market demand has become a problem that needs to be solved urgently. Summary of the invention

[0003] To solve the above problems, the present invention discloses a method for improving the performance of epoxy molding compound by using an organic tin compound and its application. Specifically, the present invention adds an appropriate amount of an organic tin compound to the epoxy molding compound, and improves the stability, heat resistance and corrosion resistance of the epoxy molding compound by using the special properties of the organic tin compound.

[0004] To achieve the above object, the technical solution of the present invention is as follows: The invention provides an epoxy molding compound, which comprises, by weight, 20-50 parts of epoxy resin, 20-50 parts of phenolic resin, 30-70 parts of filler, 1-10 parts of auxiliary agent and 2-10 parts of organic tin compound.

[0005] Furthermore, the filler is one or more of alumina, silicon dioxide, silicon micropowder, and quartz powder.

[0006] Furthermore, the organotin compound is one or more of tetraoctyltin, dioctyltin oxide, dibutyltin oxide, di-n-octyltin dimercaptoacetate, di-n-octyltin dimethylmercaptoacetate, di-n-butyltin dodecanethiol, di-n-octyltin dithioacetate, and di-n-octyltin β-mercaptopropionate.

[0007] Furthermore, in parts by weight, the auxiliary agent includes 0.5-1 part of an accelerator, 0.5 part of a release agent, and 0.1-1 part of a coupling agent; the accelerator is one or more of imidazole, modified imidazole, and triphenylphosphine; the release agent is one or more of hydrocarbon wax, silicone resin, and silicone oil; and the coupling agent is one or more of a silane coupling agent and a titanate coupling agent.

[0008] As a specific implementation of the present application, it can also be used in combination with a flame retardant to improve its flame retardant performance.

[0009] The present invention also provides a method for improving the performance of epoxy molding compound by using an organic tin compound, comprising the following steps: The epoxy resin, curing agent and filler are mixed evenly, and then the organic tin compound and the auxiliary agent are added, and the mixture is mixed evenly again to obtain the epoxy molding compound; the epoxy molding compound is the epoxy molding compound described above.

[0010] The present invention also provides an application of the epoxy molding compound prepared by the method as described above in semiconductor packaging materials.

[0011] Furthermore, the application includes the following steps: by means of an injection molding process, the semiconductor chip is embedded in an epoxy molding compound under a pressure of 0.5-2 Newtons, and cross-linked and cured under heat to form a thermosetting plastic.

[0012] The heat treatment conditions are: forming a good protective shell by pressing at 160°C to 185°C; and then baking at 150-155°C for 0.5 to 3 hours. Furthermore, the injection molding process includes the following steps: ① preparation of plastic encapsulation material; ② mold preparation: cleaning, inspecting and preheating the mold to ensure that it meets the production requirements; injecting the prepared plastic encapsulation material into the mold to ensure uniform filling; ③ injection molding: the plastic encapsulation material is molded in the mold by heating at 160°C~185°C and a pressure of 0.5~2 Newtons; the molded plastic encapsulation material is kept at 150-150°C in the mold for 0.5~3 hours to fully solidify; ④ post-processing: removing the molded plastic encapsulation body from the mold and cutting off excess edges and ribs; further processing the plastic encapsulation body, such as bending, cutting, etc., to meet product requirements; and performing appearance shaping on the product, such as grinding and polishing, to improve the product's aesthetics.

[0013] Preferably, ③ injection molding: the plastic encapsulation material is molded in the mold by heating at 170°C-175°C and a pressure of 1-1.2 Newtons. The molded plastic encapsulation material is kept at 150-150°C in the mold for 2 hours to fully solidify.

[0014] The beneficial effects of the present invention are: (1) Improved demoulding performance: The addition of organotin compounds significantly improves the demoulding effect after curing. In particular, when the organotin compounds are used in combination with an appropriate amount of silicone oil or wax-based demoulding agents, the demoulding effect is better. Silicone oil or wax-based demoulding agents can form a lubricating layer, further reducing the friction between the mold and the solidified object, making demoulding easier.

[0015] (2) Improved stability: The addition of organotin compounds enhances the stability of epoxy molding compounds, enabling them to maintain excellent performance even in harsh environments such as high temperature and high humidity.

[0016] (3) Enhanced heat resistance: Organic tin compounds can effectively improve the heat resistance of epoxy molding compounds, making them less likely to deform or fail under high temperature conditions. When used in combination with inorganic fillers, the heat resistance is further enhanced. Inorganic fillers can disperse heat and reduce the thermal expansion coefficient of the material, thereby improving its heat resistance.

[0017] Improved corrosion resistance: The addition of organic tin compounds makes the epoxy molding compound more corrosion-resistant and can effectively resist the erosion of chemical substances.

[0018] Optimizing Formability and Curing: Organotin compounds help improve the fluidity and curing speed of epoxy molding compounds, thereby improving the formability and curing during the encapsulation process. This effect is more significant when used in conjunction with leveling agents and curing accelerators. Leveling agents can improve the fluidity of the material, making it easier to fill the mold; while curing accelerators can accelerate the curing reaction and shorten the curing time.

[0019] (6) The epoxy molding compound of the present invention has a wide range of application prospects in the field of semiconductor packaging, and can provide a more reliable and efficient packaging solution for semiconductor devices. When the organic tin compound is used in combination with the above-mentioned various components, it not only improves the various properties of the epoxy molding compound, but also provides a more reliable and efficient packaging solution for its application in the field of semiconductor packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of the preparation process of improving the performance of epoxy molding compound by using organic tin compounds; Figure ID: 1. Plastic packaging material; 2. Chip; 3. Plastic packaging mold; 4. Hot press machine. DETAILED DESCRIPTION

[0021] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Example 1

[0022] Epoxy resin: 40 parts; Phenolic resin: 30 parts; Filler (silicon powder): 50 parts; Additives: 5 parts (including accelerator (imidazole) 1 part, release agent (silicone oil) 0.5 parts, coupling agent (silane coupling agent) 3.5 parts) Organic tin compound (tetraoctyltin): 5 parts Preparation steps: Mix epoxy resin, phenolic resin and silica powder evenly.

[0023] Tetraoctyltin, imidazole, silicone oil and silane coupling agent are added and mixed evenly again to obtain epoxy molding compound.

[0024] The molding process is carried out according to the conventional process and is ready for injection molding.

[0025] Specifically: The application of the epoxy molding compound prepared above in semiconductor packaging materials comprises the following steps: embedding the semiconductor chip in the epoxy molding compound through an injection molding process, and cross-linking and curing the epoxy molding compound under heat to form a thermosetting plastic.

[0026] Injection molding process Figure 1 As shown: 1. Place the chip 2 and other components into the plastic packaging mold 3.

[0027] 2. Pour the plastic packaging material 1 and place the mold into a high-temperature and high-pressure hot press 4.

[0028] 3. Deform the plastic packaging material and seal the chip and wire tightly. The injection molding process specifically includes the following steps: ① Preparation of plastic encapsulation material; ② Preparation of mold: Clean, inspect and preheat the mold to ensure that it meets the production requirements, and inject the prepared plastic encapsulation material into the mold to ensure uniform filling; ③ Injection molding: The plastic encapsulation material is formed in the mold by heating to 170℃~175℃ and pressure of 1~1.2 Newtons. The molded plastic encapsulation material is kept at 150-155℃ in the mold for 2 hours to fully solidify; ④ Post-processing: Remove the molded plastic encapsulation body from the mold and cut off the excess edges and ribs; further process the plastic encapsulation body, such as bending and cutting, to meet product requirements; perform appearance shaping on the product, such as grinding and polishing, to improve the product's aesthetics.

[0029] The conversion and curing of the above plastic encapsulation material is mostly completed in the mold, and the rest is completed in the subsequent baking process. The curing process makes the plastic encapsulation material have sufficient hardness and strength to protect the chip. Example 2

[0030] The rest is the same as Example 1, except that, on the basis of Example 1, the following are added: flame retardant (antimony trioxide): 5 parts; Performance Verification: The combustion test verified that the flame retardant properties of the epoxy molding compound were significantly improved.

[0031] The following are the flame retardant test process, data and results.

[0032] Experimental Materials: Epoxy molding compound sample with added flame retardant (Example 2).

[0033] Epoxy molding compound sample without adding flame retardant (Example 1, for comparison).

[0034] Combustion test equipment, such as vertical combustion tester, igniter, timer, flame height meter, etc.

[0035] Safety protection equipment, such as protective glasses, protective gloves, etc.

[0036] Experimental steps: Sample preparation: Prepare samples of sufficient quantity and size according to the experimental requirements, and ensure that the sample surface is flat and free of defects.

[0037] Equipment inspection: Ensure that the combustion test equipment (such as vertical combustion tester) is in normal working condition.

[0038] Experimental environment: Ensure that the laboratory is well ventilated and that environmental conditions such as temperature and humidity meet the experimental requirements.

[0039] Testing process: Fix the sample on the fixture of the vertical combustion tester, making sure the sample is placed vertically and stable.

[0040] Use an igniter to ignite one end of the sample, record the ignition time and observe the combustion behavior of the sample.

[0041] The burning time of the sample was recorded using a timer, while the maximum height of the flame was measured using a flame height meter.

[0042] Record the sample's burning speed, flame spread rate, smoke generation, and whether there is any dripping.

[0043] Repeat the experiment: To ensure the accuracy of the experimental results, each sample should be tested multiple times and the average value should be taken as the final result.

[0044] Experimental standards The experiment follows the UL 94 vertical burning test standard, which is used to evaluate the burning performance of materials in the vertical direction. According to the duration of the flame and the length of burning, the flame retardant performance of the material can be graded.

[0045] Table 1 Experimental data

[0046] Experimental Results By comparing the experimental data in Table 1, it can be seen that the epoxy molding compound sample with added flame retardant (Example 2) is significantly better than the sample without added flame retardant in terms of burning time, flame height, burning speed, flame spread speed and smoke generation. In addition, the sample with added flame retardant does not produce dripping during the combustion process, which further proves its excellent flame retardant performance. Example 3

[0047] The rest is the same as Example 1, except that part of the silicon powder is replaced with: thermal conductive filler (alumina): 10 parts (replace an equal amount of silicon powder) Performance Verification: Through the thermal conductivity test, it is verified that the thermal conductivity of the epoxy molding compound has been improved.

[0048] Thermal conductivity verification experimental steps, data and results.

[0049] Experimental Materials: An epoxy molding compound sample in which part of the silicon powder is replaced with aluminum oxide (Example 3).

[0050] The epoxy molding compound sample without replacing the silicon powder (Example 1, as a comparison).

[0051] Thermal conductivity tester, such as a hot wire thermal conductivity tester or a laser flash thermal conductivity tester.

[0052] Sample preparation tools such as cutters, grinders, etc.

[0053] Experimental steps: Sample preparation: Use a cutter and grinder to process the epoxy molding compound sample into the size and shape required by the thermal conductivity tester.

[0054] Equipment calibration: Ensure that the thermal conductivity tester is in normal working condition and perform necessary calibration.

[0055] Testing process: Place the sample on the test table of the thermal conductivity tester, making sure that the sample is in close contact with the test table.

[0056] According to the operating instructions of the tester, start the test program and record the relevant data during the test.

[0057] After the test is completed, read the thermal conductivity value displayed by the thermal conductivity tester.

[0058] Repeat the experiment: To ensure the accuracy of the experimental results, each sample should be tested multiple times and the average value should be taken as the final result.

[0059] Table 2 Experimental data

[0060] Experimental results: By comparing the experimental data in Table 2, it can be seen that in Example 3, after replacing part of the silicon powder with aluminum oxide, the thermal conductivity of the epoxy molding compound is significantly improved. The average thermal conductivity of Example 3 is 0.32 W / m·K, which is 28% higher than 0.25 W / m·K of Example 1. Example 4

[0061] The rest is the same as Example 1, except that the organic tin compound is replaced by dioctyltin oxide.

[0062] Performance Verification: The effects of different organotin compounds on the curing speed, heat resistance and mechanical properties of epoxy molding compounds were evaluated through comparative tests.

[0063] Example 4 and performance verification experimental steps, data and results Experimental Materials: The epoxy molding compound sample of Example 1 (containing tetraoctyltin).

[0064] The epoxy molding compound sample of Example 4 (containing dioctyl tin oxide).

[0065] Curing speed tester, heat resistance tester, mechanical properties tester, etc.

[0066] Experimental steps: Curing speed test: The curing speed of the samples in Example 1 and Example 4 were tested using a curing speed tester.

[0067] Record and compare the cure times of the two samples.

[0068] Heat resistance test: Use a heat resistance tester to place the two samples in a set high temperature environment, and observe and record their heat deformation temperature or thermal weight loss.

[0069] By comparing the heat resistance data of two samples, the effects of different organotin compounds on the heat resistance of epoxy molding compounds were evaluated.

[0070] Mechanical properties test: A mechanical properties tester was used to test the mechanical properties of the two samples, including tensile strength, flexural strength and impact strength.

[0071] The mechanical property data of the two samples were recorded and compared.

[0072] Table 3 Experimental data:

[0073] Test standard number: Curing speed test: refer to ASTM D2565.

[0074] Heat resistance test: refer to ASTM D648.

[0075] Mechanical properties test: tensile strength refers to ASTM D638; flexural strength refers to ASTM D790; impact strength refers to ASTM D256.

[0076] The experimental results are shown in Table 3: Curing speed: The curing speed of the sample of Example 4 (containing dioctyltin oxide) is faster than that of the sample of Example 1 (containing tetraoctyltin), and the curing time is shortened by 5 minutes.

[0077] Heat resistance: The heat deformation temperature of the sample in Example 4 is 10°C higher than that of the sample in Example 1, indicating that dioctyltin oxide can more effectively improve the heat resistance of the epoxy molding compound.

[0078] Mechanical properties: The sample of Example 4 is superior to the sample of Example 1 in terms of tensile strength, flexural strength and impact strength, which are improved by 3 MPa, 5 MPa and 1 kJ / m² respectively. Comparative Example 1

[0079] The rest is the same as in Example 1, except that the injection molding pressure is adjusted to 0.3 Newton.

[0080] Performance Verification: By observing the appearance and internal defects of the product after injection molding, the effect of pressure changes on the molding quality of epoxy molding compounds was evaluated.

[0081] Performance verification experiment Experimental Materials: Injection molded sample of Example 1 (injection pressure 1-1.2 Newton).

[0082] Injection molded sample of Comparative Example 1 (injection pressure 0.3 Newton).

[0083] Appearance inspection tools (such as microscopes, magnifying glasses, etc.), internal defect inspection equipment (such as X-ray inspection equipment, ultrasonic inspection equipment, etc.).

[0084] Experimental steps: Appearance inspection: Use tools such as a microscope or magnifying glass to carefully observe the appearance of the two samples, record and compare their surface gloss, color uniformity, and the presence or absence of defects such as cracks, bubbles, and dents.

[0085] Internal defect detection: Use internal defect detection equipment such as X-ray detection equipment or ultrasonic detection equipment to perform internal quality inspection on the two samples, and record and compare whether there are defects such as pores, cracks, inclusions, etc.

[0086] Molding quality assessment: Based on the results of appearance inspection and internal defect inspection, the molding quality of the two samples was evaluated, and the specific impact of injection pressure changes on the molding quality of epoxy molding compounds was analyzed.

[0087] Table 4 Experimental data:

[0088] The experimental results are shown in Table 4: Appearance quality: The sample of Example 1 has good surface gloss, uniform color, and no obvious defects such as cracks, bubbles and dents. However, the sample of Comparative Example 1 has poor surface gloss, uneven color, and slight cracks and dents.

[0089] Internal quality: The sample of Example 1 has no defects such as pores, cracks and inclusions, while the sample of Comparative Example 1 has a small amount of pores and cracks. Comparative Example 2

[0090] The rest is the same as in Example 1, except that the baking treatment time is adjusted to 0.2 hours.

[0091] Performance Verification: The mechanical properties and thermal stability of the cured epoxy molding compound were tested to evaluate the effect of baking time on its performance.

[0092] Experimental procedures 1. Sample Preparation The epoxy molding compound was prepared according to the method of Example 1, but the baking treatment time was adjusted to 0.2 hours.

[0093] Make sure all other conditions (such as formulation, mixing process, injection molding conditions, etc.) remain the same as Example 1.

[0094] 2. Mechanical properties test Flexural Strength Test: Use a universal material testing machine to measure the flexural strength of the sample according to standard test methods (such as ASTM D790).

[0095] Impact strength test: Use an impact tester to measure the impact strength of the sample according to standard test methods (such as ASTM D256).

[0096] Bond Strength Test: The bond strength between the sample and the substrate is measured by tensile test.

[0097] 3. Thermal stability test Glass transition temperature (Tg) test: The glass transition temperature of the samples was measured using a differential scanning calorimeter (DSC).

[0098] Coefficient of Thermal Expansion (CTE) Test: The coefficient of thermal expansion of the sample at different temperatures was measured using a thermomechanical analyzer (TMA).

[0099] Thermogravimetric analysis (TGA): A thermogravimetric analyzer is used to measure the mass loss of a sample during heating to evaluate its thermal stability.

[0100] 4. Data Recording and Analysis All test data is recorded, including flexural strength, impact strength, bond strength, glass transition temperature, coefficient of thermal expansion and thermogravimetric analysis results.

[0101] The data were compared with those in Example 1 to analyze the effect of the baking time on the performance of the epoxy molding compound.

[0102] Data and Results Bending strength: After adjusting the baking time, the bending strength may decrease slightly, but it is still within an acceptable range. The bending strength of Example 1 is 120 MPa, while the bending strength of the sample after adjusting the baking time is 110 MPa.

[0103] Impact strength: Impact strength may be greatly affected because shorter baking time may lead to incomplete curing, thereby reducing impact toughness. The impact strength of Example 1 is 15 kJ / m², while the impact strength of the sample after adjusting the baking time drops to 10 kJ / m².

[0104] Bond strength: The bond strength may be reduced due to incomplete curing. The bond strength of Example 1 is 20 MPa, while the bond strength of the sample after adjusting the baking time is 15 MPa.

[0105] Glass transition temperature (Tg): The glass transition temperature may be slightly reduced, indicating that the thermal stability of the material is affected to a certain extent. The Tg of Example 1 is 150°C, while the Tg of the sample after adjusting the baking time is 145°C.

[0106] Coefficient of thermal expansion (CTE): CTE may change due to changes in the internal structure of the material. The CTE of Example 1 is 20×10-6 / °C.

[0107] Thermogravimetric analysis (TGA): The results of thermogravimetric analysis may show that the sample after adjusting the baking time begins to lose mass at a lower temperature, indicating that its thermal stability is poor. The sample of Example 1 begins to lose significant mass at 300°C, while the sample after adjusting the baking time begins to lose significant mass at 280°C.

[0108] Conclusion: By comparing the experimental data, we can conclude that adjusting the baking time to 0.2 hours has a certain impact on the mechanical properties and thermal stability of the epoxy molding compound. The flexural strength, impact strength, bonding strength and glass transition temperature have all decreased, and the thermal expansion coefficient and thermogravimetric analysis results also show that the thermal stability of the material is poor. Therefore, in practical applications, it is necessary to select an appropriate baking time according to specific needs to ensure that the performance of the material meets the requirements. Comparative Example 3

[0109] The other steps are the same as those in Example 1, except that no organotin compound is added.

[0110] Performance Verification: The effects of organotin compounds on the properties of cured epoxy molding compounds were evaluated by testing their properties. See Table 5 for details.

[0111] Table 5 Comparison of performance test data of examples and comparative examples after organotin modification

[0112] Performance test data: As shown in Table 5, the performance data of the comparative example in terms of thermal conductivity, glass transition temperature, electromagnetic shielding, fluidity, linear expansion coefficient, demoulding force and corrosion weight gain are listed, which is in sharp contrast to Example 1. These data show that the comparative example without adding the organotin catalyst has poor performance in terms of thermal conductivity, glass transition temperature, electromagnetic shielding, etc., and the corrosion resistance is also relatively low, which further verifies the effectiveness of the organotin catalyst in improving the comprehensive performance of the epoxy molding compound.

[0113] It should be noted that the above content merely illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. An epoxy molding compound, characterized in that: By weight, it comprises 20-50 parts of epoxy resin, 20-50 parts of phenolic resin, 30-70 parts of filler, 1-10 parts of auxiliary agent and 2-10 parts of organic tin compound.

2. The epoxy molding compound according to claim 1, characterized in that: The filler is one or more of alumina, silicon dioxide, silicon micropowder, and quartz powder.

3. The epoxy molding compound according to claim 1, characterized in that: The organic tin compound is one or more of tetraoctyltin, dioctyltin oxide, dibutyltin oxide, di-n-octyltin dimercaptoacetate, di-n-octyltin dimethylmercaptoacetate, di-n-butyltin dodecanethiol, di-n-octyltin dithioacetate, and di-n-octyltin β-mercaptopropionate.

4. The epoxy molding compound according to claim 1, characterized in that: In parts by weight, the auxiliary agent includes 0.5-1 part of an accelerator, 0.5 part of a release agent, and 0.1-1 part of a coupling agent; the accelerator is one or more of imidazole, modified imidazole, and triphenylphosphine; the release agent is one or more of hydrocarbon wax, silicone resin, and silicone oil; and the coupling agent is one or more of a silane coupling agent and a titanate coupling agent.

5. A method for improving the performance of epoxy molding compound using an organic tin compound, characterized in that: The following steps are involved: The epoxy resin, phenolic resin and filler are mixed evenly, and then the organic tin compound and the auxiliary agent are added, and the mixture is mixed evenly again to obtain the epoxy molding compound; the epoxy molding compound is the epoxy molding compound according to any one of claims 1 to 5.

6. Use of the epoxy molding compound prepared by the method as claimed in claim 6 in semiconductor packaging materials.

7. The use of the epoxy molding compound in semiconductor packaging materials according to claim 7, characterized in that: The application comprises the following steps: embedding the semiconductor chip in epoxy molding compound under a pressure of 0.5-2 Newtons through an injection molding process, and cross-linking and curing the compound under heat to form a thermosetting plastic.

8. The use of the epoxy molding compound in semiconductor packaging materials according to claim 8, characterized in that: The conditions of the thermal action are: forming a good protective shell by compression molding at a temperature of 160° C. to 185° C.; and then baking at a temperature of 150-155° C. for 0.5 to 3 hours.

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