Local gradient silicon-aluminum electronic packaging material forming method

Abstract

The invention relates to the field of material forming, and discloses a local gradient silicon-aluminum electronic packaging material forming method which comprises the following steps: carrying out micro-nano structure pretreatment on a gradient silicon-aluminum material to be compounded and a heterogeneous metal interface; the pressure wave frequency is determined according to the used ultrasonic wave frequency, the ratio of the pressure wave frequency to the ultrasonic wave frequency is 1: 3-1: 5, and in the interface treatment process of the ultrasonic wave-electric field synergistic effect, periodic pressure wave intensity change is executed, and stable output of the ultrasonic wave and the electric field is maintained; a to-be-composited material is placed in a special treatment cavity, triple physical field combination is applied according to a specific sequence, an electric field is applied firstly, then ultrasonic waves are applied while the electric field is maintained, and finally pressure waves with intensity gradient are applied while the first physical field and the second physical field are maintained; carrying out hot press molding and quality detection on the treated material; according to the method, the problem of unstable quality caused by random distribution of bubbles in a traditional method is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of material forming, and more specifically, it relates to a forming method for a locally gradient silicon-aluminum electronic packaging material. Background Art

[0002] In high-reliability electronic packaging fields such as aerospace and military electronics, strict requirements are imposed on the airtightness and long-term reliability of materials. The airtightness needs to reach 1×10^-7 Pa·m 3 / s or more, and it does not fail during long-term use (more than 10 years) in complex environments.

[0003] There is a technical difficulty in the existing processes: cavitation effects are generated by ultrasonic waves in the liquid-phase interface activator, forming a large number of microbubbles. These microbubbles will migrate directionally under the action of an electric field and accumulate at specific positions at the interface, forming a microscopic bubble layer. During the subsequent hot pressing process, these bubbles cannot be completely discharged, and finally micropores are formed in the interface region, becoming channels for water vapor penetration and corrosion, reducing the airtightness and long-term reliability of the electronic packaging material, and leading to packaging failure.

[0004] Traditional processes mainly adopt methods such as increasing the hot pressing force or prolonging the hot pressing time to remove bubbles, but these methods will cause excessive deformation or performance deterioration of the material, and the effects are limited and cannot fundamentally solve the microbubble problem. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a forming method for a locally gradient silicon-aluminum electronic packaging material.

[0006] The present invention provides a forming method for a locally gradient silicon-aluminum electronic packaging material, including the following steps:

[0007] Step 1: Perform micro-nano structure pretreatment on the interface between the gradient silicon-aluminum material to be compounded and the heterogeneous metal;

[0008] Step 2: Determine the pressure wave frequency according to the ultrasonic frequency used, make the ratio of the pressure wave frequency to the ultrasonic frequency be 1:3 to 1:5, manufacture and install a pressure wave source, and construct a pressure wave-ultrasonic synchronous control system to achieve synchronization between the pressure wave peak and the ultrasonic cavitation negative pressure stage;

[0009] Step 3: During the interface treatment under the synergistic action of ultrasonic waves and an electric field, perform periodic changes in the pressure wave intensity, including a low-intensity stage, a medium-intensity stage, and a high-intensity stage, while maintaining the stable output of ultrasonic waves and the electric field;

[0010] Step 4: Place the composite material to be treated in a dedicated processing chamber, and apply a triple physical field combination in a specific sequence. First, apply an electric field, then apply ultrasonic waves while maintaining the electric field, and finally apply a pressure wave with an intensity gradient while maintaining the previous two fields.

[0011] Step 5: Thermally press and form the treated material and conduct quality inspection.

[0012] Preferably: The micro-nano structure pretreatment in Step 1 includes: mechanically roughening the gradient silicon-aluminum material to be compounded and the surface of the heterogeneous metal to form a microscopic rough structure with a depth of 5 - 15 μm; adopting a chemical activation process for the material interface to remove surface oxides and impurities; coating a dedicated activator on the interface to be bonded, and controlling the coating thickness of the activator within the range of 10 - 30 μm.

[0013] Preferably: The synchronization control system in Step 2 achieves a phase difference control accuracy of the pressure wave and the ultrasonic wave of not less than ±5°.

[0014] Preferably: In the periodic pressure wave intensity change mode in Step 3: The low-intensity stage lasts for 10 - 30 seconds, and the amplitude of the pressure wave is 30 - 50% of the reference value; the medium-intensity stage lasts for 20 - 60 seconds, and the amplitude of the pressure wave is 60 - 80% of the reference value; the high-intensity stage lasts for 5 - 15 seconds, and the amplitude of the pressure wave is 90 - 120% of the reference value.

[0015] Preferably: The ultrasonic power density maintained in Step 3 is 15 - 25 W / cm 2 , and the electric field strength is 50 - 150 V / mm.

[0016] Preferably: The duration of applying the electric field in Step 4 is 30 - 60 seconds, the duration of applying the ultrasonic wave is 60 - 120 seconds, and the duration of applying the pressure wave is 120 - 180 seconds.

[0017] Preferably: In Step 4, one side of the dedicated processing chamber is configured as a region with relatively weak pressure wave intensity, and the other side is configured as a region with relatively strong pressure wave intensity, forming a pressure wave intensity gradient from the outside to the inside of the interface.

[0018] Preferably: Step 4 also includes real-time monitoring of the change in the acoustic characteristics of the interface region, and evaluating the degree and effect of bubble migration by analyzing the acoustic response signal.

[0019] Preferably: The thermoforming in Step 5 is carried out under the conditions of a temperature of 450 - 550 °C and a pressure of 30 - 50 MPa, and the thermoforming time is 30 - 90 minutes.

[0020] Preferably, the quality inspection in step 5 includes interface bonding strength test, airtightness test, interface microstructure analysis and thermal cycle test. The qualified standard for the airtightness test is that the airtightness is not higher than 1×10^ -7 Pa·m 3 / s. The thermal cycle test is carried out in the temperature range of -55°C to +125°C, and the number of cycles is 100 - 500 times.

[0021] The beneficial effects of the present invention are as follows: improving the airtightness of the gradient silicon-aluminum electronic packaging material. The airtightness of the interface treated by the pressure wave modulation forming method is effectively improved, meeting the requirements of high-reliability applications such as aerospace and military electronics.

[0022] Enhancing the interface bonding strength and long-term reliability. The interface treated by the triple physical field synergistic treatment has a bonding strength increased by 40 - 60% compared with the traditional process, reaching 100 - 120 MPa; the interface stability under thermal cycle conditions is improved, and it can withstand more than 500 thermal cycle tests without interface delamination or microcracks.

[0023] Shortening the production cycle and reducing energy consumption. Due to the control of microbubbles, the subsequent hot pressing time is shortened by 20 - 30%, the overall production cycle is shortened by more than 25%, and the energy consumption is reduced by about 20%, improving production efficiency and economy.

[0024] Improving product consistency and yield. The quality fluctuation between product batches is controlled, the product consistency is improved, and the yield is increased from the traditional 85 - 90% to more than 95%, reducing production costs.

[0025] Expanding the application range of the gradient silicon-aluminum electronic packaging material. By solving the problems of airtightness and long-term reliability, the material can be applied to more demanding working environments, such as electronic packaging under extreme conditions such as deep sea and polar regions, expanding the application fields. Description of the Drawings

[0026] Figure 1 are the airtightness test results of the samples prepared by different process methods of the present invention;

[0027] Figure 2 are the interface micropore analysis results of the samples prepared by different process methods of the present invention;

[0028] Figure 3 is the box plot of the airtightness distribution of three groups of samples of the present invention;

[0029] Figure 4 are the initial interface bonding strength test results of the samples prepared by different process methods of the present invention;

[0030] Figure 5 is the change of the interface bonding strength of the samples prepared by different process methods after the thermal cycle test of the present invention;

[0031] Figure 6 It is the change trend of the interfacial bonding strength of the three groups of samples of the present invention during the thermal cycle test;

[0032] Figure 7 It is the comparison of the interfacial crack density of the samples after generating different numbers of thermal cycles of the present invention;

[0033] Figure 8 It is the comparison of the production cycles of different process methods of the present invention;

[0034] Figure 9 It is the comparison of the energy consumption of different process methods of the present invention;

[0035] Figure 10 It is the proportion of the time of each stage of the three process methods of the present invention in the total production cycle;

[0036] Figure 11 It is the quality consistency test result of the products produced by different process methods of the present invention;

[0037] Figure 12 It is the comparison of the product qualification rates of different process methods of the present invention;

[0038] Figure 13 It is the distribution of the defect types of the three process products of the present invention;

[0039] Figure 14 It is the airtightness retention rate of the samples of different process methods of the present invention after the extreme environment test;

[0040] Figure 15 It is the bonding strength retention rate of the samples of different process methods of the present invention after the extreme environment test;

[0041] Figure 16 It is the comprehensive performance retention rate of the three process samples of the present invention under different extreme environments;

[0042] Figure 17 It is the application scenario adaptability analysis of the samples of different process methods of the present invention. Detailed implementation manners

[0043] Now, the subject matter described herein will be discussed with reference to exemplary embodiments. It should be understood that discussing these embodiments is only to enable those skilled in the art to better understand and thus implement the subject matter described herein. Without departing from the scope of protection of the content of this specification, changes can be made to the functions and arrangements of the elements discussed. Each example can omit, substitute, or add various processes or components as needed. Additionally, the features described in some examples can also be combined in other examples.

[0044] In at least one embodiment of the present invention, a forming method for a local gradient silicon-aluminum electronic packaging material is disclosed, including the following steps:

[0045] Step 1: Interface micro-nano structure pretreatment

[0046] The gradient silicon-aluminum material to be compounded and the heterogeneous metal (such as copper, magnesium or steel) are surface-treated to form an interface micro-nano structure conducive to bonding. The specific process includes:

[0047] (1.1) Mechanically roughen the surfaces of the gradient silicon-aluminum material to be compounded and the heterogeneous metal to form a microscopic rough structure with a depth of 5 - 15 μm. This operation increases the interface mechanical interlocking area and improves the basic bonding strength.

[0048] (1.2) Adopt a chemical activation process for the material interface to remove surface oxides and impurities and improve surface activity. Select an appropriate activation solution according to the type of heterogeneous metal, and rinse and dry with deionized water after treatment.

[0049] (1.3) Coat a special activator on the interface to be bonded. The activator is in a liquid state and contains components that promote interface activation. The coating thickness of the activator is controlled within the range of 10 - 30 μm to ensure uniform coverage.

[0050] Step 2: Determination and implementation of the pressure wave - ultrasonic frequency ratio

[0051] In this step, a specific frequency ratio relationship between the pressure wave and the ultrasonic wave is established to inhibit the formation of cavitation bubbles. The specific process is as follows:

[0052] (2.1) According to the ultrasonic frequency used (usually 18 - 60 kHz), determine the optimal pressure wave frequency. Experimental data show that when the ratio of the pressure wave frequency to the ultrasonic wave frequency is 1:3 to 1:5, the effect of inhibiting the formation of cavitation bubbles is the best. For example, when using 40 kHz ultrasonic waves, the pressure wave frequency is selected in the range of 8 - 13 kHz to obtain the best effect. This specific frequency ratio enables the pressure wave to provide additional pressure during the cavitation negative pressure stage of the ultrasonic wave to inhibit bubble nucleation.

[0053] (2.2) Fabricate and install a pressure wave source capable of generating a specific frequency pressure wave, and fix it on the processing cavity to effectively transfer the pressure wave to the interface area. The installation position of the pressure wave source takes into account the propagation path of the pressure wave to ensure its specific phase relationship with the ultrasonic wave.

[0054] (2.3) Construct a pressure wave - ultrasonic synchronization control system to achieve precise phase control of the two waves. The wave peak of the pressure wave is synchronized with the cavitation negative pressure stage of the ultrasonic wave to form a synergistic effect in the time domain. The phase difference control accuracy is not less than ±5° to obtain the best inhibition effect.

[0055] Step 3: Processing of the change in the intensity of the periodic pressure wave

[0056] In this step, by implementing the change in the intensity of the periodic pressure wave, the dissolution and rupture of the already formed microbubbles are achieved. The specific process is as follows:

[0057] (3.1) During the interfacial treatment under the synergistic action of ultrasonic waves and electric fields, a periodic pressure wave intensity change pattern is executed. A complete cycle of pressure wave intensity change includes: a low-intensity stage (lasting 10 - 30 seconds), a medium-intensity stage (lasting 20 - 60 seconds), and a high-intensity stage (lasting 5 - 15 seconds). The amplitude of the pressure wave in the low-intensity stage is 30 - 50% of the reference value, which is used to ensure the full progress of the interfacial reaction; the amplitude of the pressure wave in the medium-intensity stage is 60 - 80% of the reference value, which promotes the dissolution of the gas inside the microbubbles; the amplitude of the pressure wave in the high-intensity stage is 90 - 120% of the reference value, which causes the already-shrunk microbubbles to rupture rapidly.

[0058] (3.2) According to the material combination and the characteristics of the interfacial activator, the parameters of the pressure wave intensity change cycle are adjusted. For example, for the composite of gradient silicon-aluminum material with a high silicon content and copper, the high-intensity stage is extended to 15 - 20 seconds; for the composite of gradient silicon-aluminum material with a low silicon content and magnesium, the high-intensity stage is controlled within the range of 5 - 10 seconds.

[0059] (3.3) During the periodic pressure wave change process, the stable output of ultrasonic waves and electric fields is maintained. The ultrasonic power density is kept within the range of 15 - 25 W / cm 2 range, and the electric field intensity is kept within the range of 50 - 150 V / mm, forming a synergistic action environment of the three physical fields.

[0060] Step 4: Control of the directional migration of interfacial bubbles

[0061] In this step, by applying a triple combination of pressure wave - ultrasonic wave - electric field in a specific sequence, a directional stress gradient field in the interfacial region is formed, which promotes the directional migration and discharge of the residual bubbles. The specific process is as follows:

[0062] (4.1) Before the final hot pressing stage, the composite material to be processed is placed in a special treatment cavity, which can simultaneously apply pressure waves, ultrasonic waves, and electric fields and form an intensity gradient in a specific direction. One side of the treatment cavity (usually the outer side of the interface) is configured as a region with a relatively weak pressure wave intensity, and the other side (usually the inner side of the interface) is configured as a region with a relatively strong pressure wave intensity, forming a pressure wave intensity gradient from the outer side to the inner side of the interface.

[0063] (4.2) Apply a combination of triple physical fields in a specific sequence. The sequence is as follows: First, apply an electric field (50 - 150 V / mm) for 30 - 60 seconds to charge the microbubbles and align them directionally. Then, while maintaining the electric field, apply ultrasonic waves (15 - 25 W / cm 2 ) for 60 - 120 seconds to vibrate the microbubbles and cause them to migrate along the direction of the electric field. Finally, while maintaining the previous two fields, apply a pressure wave with an intensity gradient for 120 - 180 seconds to enhance the driving force for the directional migration of the bubbles. This sequence utilizes the synergistic effect of the three physical fields to form a composite driving force, prompting the microbubbles to migrate to the outside of the interface along a predetermined direction (usually perpendicular to the interface direction).

[0064] (4.3) During the bubble migration process, continuously monitor the changes in the acoustic properties of the interface region. By analyzing the acoustic response signals, evaluate the degree and effect of bubble migration, and adjust the parameters if necessary to ensure the sufficiency and effectiveness of bubble migration.

[0065] Step 5: Final hot pressing and quality inspection

[0066] After completing the interface bubble control treatment, perform hot pressing and quality inspection. The specific process is as follows:

[0067] (5.1) Load the gradient silicon-aluminum material and the heterogeneous metal that have been treated by the triple physical field synergy into a hot pressing mold, and perform hot pressing at appropriate temperatures (usually 450 - 550 °C) and pressures (usually 30 - 50 MPa). Since the interface bubbles have been effectively controlled in the previous stage, the hot pressing time in this stage is shortened by 20 - 30% compared to the traditional process, usually 30 - 90 minutes, and the specific time is determined according to the material size and complexity.

[0068] (5.2) After the hot pressing is completed, cool and perform post-treatment at a specified cooling rate (5 - 10 °C / min) to avoid thermal stress concentration and deformation caused by excessive cooling.

[0069] (5.3) Conduct quality inspection on the formed composite material, mainly including:

[0070] Interface bonding strength test: Evaluate the interface bonding strength through shear test or tensile test. The qualified standard is ≥80 MPa;

[0071] Air tightness test: Test the air tightness of the material through a helium mass spectrometer leak detector. The qualified standard is ≤1×10^-7 Pa·m 3 / s;

[0072] Interface microstructure analysis: Observe the microstructure of the interface region through a metallurgical microscope or a scanning electron microscope to evaluate the interface bonding quality and the distribution of micropores;

[0073] Thermal Cycle Test: Thermal cycle tests are performed in the temperature range of -55°C to +125°C (usually 100-500 cycles) to evaluate the interface stability of the material under temperature changes.

[0074] In order to verify the technical effect of this embodiment, a series of systematic experiments and tests were conducted on the main technical effects. The following experimental results show that the molding method can effectively solve the interface microbubble problem in the ultrasonic-electric field synergy process and significantly improve the performance and process efficiency of gradient silicon-aluminum electronic packaging materials.

[0075] Experiment 1: Verification of airtightness improvement effect

[0076] 1. Purpose of the experiment

[0077] Verify the effect of pressure wave modulation molding method on improving the airtightness of gradient silicon-aluminum electronic packaging materials.

[0078] 2. Experimental Procedure

[0079] Sample preparation: Three groups of gradient Si-Al-Cu composite material specimens were prepared, 20 in each group, with a size of 30 mm × 30 mm × 3 mm.

[0080] Group A: using traditional hot pressing molding process (control group).

[0081] Group B: conventional ultrasonic-electric field synergistic process was used.

[0082] Group C: adopts the pressure wave modulation forming method of the present invention.

[0083] 3. Preparation conditions:

[0084] The three groups of samples used the same material composition and pretreatment methods.

[0085] Group A adopted conventional hot pressing process (500°C, 40MPa, 90 minutes).

[0086] Group B used ultrasonic-electric field synergistic technology (ultrasound: 20W / cm 2 , electric field: 100 V / mm), and then hot pressing (500°C, 40 MPa, 70 min).

[0087] Group C adopted the pressure wave modulation molding method of the present invention (pressure wave to ultrasonic frequency ratio of 1:4, periodic pressure wave intensity variation, triple physical field specific sequence application), followed by hot pressing (500°C, 40MPa, 60 minutes).

[0088] 4. Air tightness test:

[0089] A helium mass spectrometer leak detector (sensitivity: 1×10^-12Pa·m 3 / s) Test the airtightness of the test samples.

[0090] Test conditions: room temperature, 1.5 MPa pressure difference, continuously detect for 30 minutes.

[0091] Each sample is tested 3 times and the average value is taken.

[0092] 5. Interface microstructure analysis:

[0093] Use a scanning electron microscope to observe the micropore distribution at the sample interface.

[0094] Randomly select 5 samples from each group, and select 5 fields of view for each sample for analysis.

[0095] Statistically analyze the number, size and distribution of the interface micropores.

[0096] 6. Experimental results

[0097] Airtightness test results:

[0098] The airtightness test results of the three groups of samples are as Figure 1 shown:

[0099] From Figure 1 it can be seen that the average airtightness of Group C samples is increased by about 413 times compared with Group A and by about 106 times compared with Group B, reaching 1×10^-9 Pa·m 3 / s level, meeting the stringent requirements of high-reliability electronic packaging.

[0100] Micropore analysis results:

[0101] By observing the microstructure of the interfaces of the three groups of samples with a scanning electron microscope, the situation of the interface micropores was statistically analyzed, and the results are as Figure 2 shown:

[0102] From Figure 2 it can be seen that the number, size and area ratio of the interface micropores of Group C samples are significantly lower than those of Group A and Group B, and the area ratio of the micropores is reduced by 98.5% and 94.9%.

[0103] Airtightness distribution and stability:

[0104] Figure 3 is the distribution of the airtightness of the three groups of samples. It can be intuitively seen that the samples prepared by the pressure wave modulation forming method have better airtightness and higher stability. This figure shows that the airtightness of Group C samples is not only much higher than that of Group A and Group B as a whole, but also the fluctuations between samples are smaller, indicating that the pressure wave modulation forming method can not only significantly improve the airtightness level, but also improve the product consistency.

[0105] The experimental results show that the pressure wave modulation forming method of the present invention can effectively inhibit the formation of interfacial microbubbles during the ultrasonic-electric field synergistic process, significantly improve the airtightness of the gradient silicon-aluminum electronic packaging material, and achieve the expected technical effect.

[0106] Experiment 2: Verification of the improvement effect of interfacial bonding strength and long-term reliability

[0107] 1. Experimental purpose

[0108] Verify the improvement effect of the pressure wave modulation forming method on the interfacial bonding strength and long-term reliability of the gradient silicon-aluminum electronic packaging material.

[0109] 2. Experimental steps

[0110] Sample preparation: Using the same method as in Experiment 1, prepare three groups of gradient silicon-aluminum-copper composite material specimens:

[0111] Group A: Using the traditional hot pressing forming process (control group).

[0112] Group B: Using the conventional ultrasonic-electric field synergistic process.

[0113] Group C: Using the pressure wave modulation forming method of the present invention.

[0114] 3. Interfacial bonding strength test:

[0115] Randomly select 10 samples from each group for the interfacial bonding strength test.

[0116] Adopt the shear test method, and the test rate is 0.5 mm / min.

[0117] Test temperature: Room temperature (25 ± 2 °C).

[0118] Record the shear force-displacement curve and the maximum shear strength.

[0119] 4. Thermal cycle test:

[0120] Randomly select 10 samples from each group for the thermal cycle test.

[0121] Temperature range: -55 °C to +125 °C.

[0122] Heating / cooling rate: 10 °C / min.

[0123] High-temperature and low-temperature dwell time: 15 minutes each.

[0124] Test cycle times: 0 times, 100 times, 300 times, 500 times, 700 times.

[0125] Take out the samples after each cycle number node for the interfacial bonding strength test.

[0126] 5. Analysis of the evolution of the interface microstructure:

[0127] The microstructure changes of the sample interface after different numbers of cycles were observed using a scanning electron microscope.

[0128] The generation, propagation, and distribution of interface cracks were analyzed.

[0129] 6. Experimental results

[0130] Test results of the initial interface bonding strength:

[0131] The test results of the initial interface bonding strength of the three groups of samples are as Figure 4 shown:

[0132] From Figure 4 it can be seen that the average interface bonding strength of group C samples increased by 62.5% compared with group A and by 32.2% compared with group B, reaching a high strength level above 100 MPa, and the standard deviation among the samples decreased significantly, indicating an improvement in product consistency.

[0133] Change in the interface bonding strength after thermal cycling tests:

[0134] The test results of the interface bonding strength of the three groups of samples after different numbers of thermal cycles are as Figure 5 shown:

[0135] From Figure 5 it can be seen that after the thermal cycling test, the attenuation of the interface bonding strength of group C samples was the smallest, and 86.1% of the initial strength was still maintained after 700 cycles, which was much higher than the strength retention rates of group A (46.9%) and group B (64.4%).

[0136] Trend of the change in the interface bonding strength:

[0137] Figure 6 The following is the trend of the change in the interface bonding strength of the three groups of samples during the thermal cycling test:

[0138] The figure shows that as the number of thermal cycles increased, the interface bonding strength of the three groups of samples all showed a downward trend, but the decrease rate of group C samples was significantly lower than that of group A and group B. After 700 thermal cycles, the interface bonding strength of group C samples was still significantly higher than the qualified standard of 80 MPa, while the samples of group A and group B failed to varying degrees.

[0139] Analysis of the evolution of the interface microstructure:

[0140] By observing the interface microstructure of the three groups of samples after different numbers of thermal cycles using a scanning electron microscope, it was found that:

[0141] Samples in group A: Obvious microcracks on the interface began to appear after 300 cycles, the cracks extended and connected after 500 cycles, and large-scale interface delamination occurred after 700 cycles.

[0142] Samples in group B: Obvious interface microcracks began to appear after 500 cycles. After 700 cycles, the crack density and length increased, but no large-scale delamination was formed.

[0143] Samples in group C: Even after 700 cycles, only a few tiny cracks appeared in the interface area, and no obvious delamination was found.

[0144] Figure 7 To generate a comparison of the interface crack density of samples after different thermal cycles:

[0145] With the increase of thermal cycle times, the interface crack density of the three groups of samples showed an upward trend, but the crack density growth rate of group C samples was much lower than that of groups A and B. After 700 thermal cycles, the interface crack density of group C samples was only 11.4% of that of group A and 24.7% of that of group B.

[0146] Based on the above experimental results, it can be seen that the pressure wave modulation molding method of the present invention significantly improves the interface bonding strength and long-term reliability of the gradient silicon-aluminum electronic packaging material, verifying the above technical effects. In particular, after 700 severe thermal cycle tests, it still maintains a high interface bonding strength and interface integrity, indicating that this method can effectively solve the long-term reliability problems existing in traditional processes.

[0147] Experiment 3: Verification of the effect of shortening production cycle and reducing energy consumption

[0148] 1. Purpose of the experiment

[0149] Verify the optimization effect of pressure wave modulation molding method on the production cycle and energy consumption of gradient silicon-aluminum electronic packaging materials.

[0150] 2. Experimental Procedure

[0151] Production batch settings:

[0152] Three production batches with different processes were set up, with each batch producing 30 gradient silicon-aluminum-copper composite packages of the same specifications.

[0153] Batch A: using traditional hot pressing molding process (control group).

[0154] Batch B: Using conventional ultrasonic-electric field synergistic process.

[0155] Batch C: adopts the pressure wave modulation molding method of the present invention.

[0156] 3. Production cycle records:

[0157] Record the time of each stage in the production process of each batch in detail, including:

[0158] Material preparation time.

[0159] Interface pretreatment time.

[0160] Physical field treatment time (ultrasonic - electric field / pressure wave - ultrasonic - electric field).

[0161] Hot pressing forming time.

[0162] Post - treatment time.

[0163] Total production cycle.

[0164] 4. Energy consumption monitoring:

[0165] Install power monitoring equipment and record the energy consumption data of each process stage

[0166] Record parameters such as equipment power, running time, total energy consumption, etc.

[0167] Calculate the average energy consumption of a single product after the production of each batch

[0168] 5. Quality consistency verification:

[0169] Sample - test the products produced by the three processes to ensure that the product quality is not affected under the condition of shortened production cycle.

[0170] The test items include: interface bonding strength, airtightness, appearance dimension accuracy, etc.

[0171] 6. Experimental results

[0172] Comparison of production cycles:

[0173] The comparison of production cycle data of the three processes is as Figure 8 shown:

[0174] From Figure 8 It can be seen that although the physical field treatment stage of Batch C is 15 minutes longer than that of Batch B, due to the effective control of interface micro - bubbles, the hot pressing forming time is significantly shortened, and the total production cycle is shortened by 22.2% compared with the traditional process, achieving the expected technical effect.

[0175] Comparison of energy consumption:

[0176] The comparison of energy consumption data of the three processes is as Figure 9 shown:

[0177] From Figure 9It can be seen that although Batch C increased energy consumption in the physical field processing stage, due to the significant shortening of the hot pressing time, the total energy consumption was reduced by 19.0% compared with the traditional process, which is close to the expected technical effect (20%).

[0178] Time proportion of each process stage:

[0179] Figure 10 The proportion of each stage of the three process methods to the total production cycle is shown:

[0180] The figure shows that in the pressure wave modulation molding method, although the physical field processing stage time accounted for 25.7%, the hot pressing stage time accounted for 34.3% from 40.0% of the traditional process, and the total production time was significantly reduced.

[0181] Quality consistency verification:

[0182] The products produced by the three processes were sampled and tested. The results are as follows: Figure 11 As shown:

[0183] from Figure 11 It can be seen that although the pressure wave modulation molding method shortens the production cycle and reduces energy consumption, the product quality has not only not decreased, but has been significantly improved in terms of consistency of interface bonding strength and airtightness, with a qualified rate of 96.7%.

[0184] Based on the above experimental results, it can be seen that the pressure wave modulation molding method of the present invention achieves the technical effect of shortening the production cycle by 22.2% and reducing energy consumption by 19.0% while ensuring or even improving product quality, thereby improving production efficiency and economy. These optimization effects are mainly due to the effective control of interface microbubbles, which significantly shortens the hot pressing molding time and reduces the energy consumption in the hot pressing molding stage.

[0185] Experiment 4: Verification of product consistency and yield rate improvement effect

[0186] 1. Purpose of the experiment

[0187] Verify the effect of pressure wave modulation molding method on improving the consistency and yield of gradient silicon-aluminum electronic packaging materials.

[0188] 2. Experimental Procedure

[0189] Batch production settings:

[0190] Three different processes were used to produce 100 gradient silicon-aluminum-copper composite packages of the same specifications.

[0191] Batch A: using traditional hot pressing molding process (control group).

[0192] Batch B: Using conventional ultrasonic-electric field synergistic process.

[0193] Batch C: The pressure wave modulation forming method of the present invention is adopted.

[0194] 3. Product inspection:

[0195] All the products produced are subject to full inspection. The inspection items include:

[0196] Appearance inspection: Surface defects, deformation, etc.

[0197] Dimensional accuracy measurement: Errors of key dimensions.

[0198] Air tightness test: Tested by a helium mass spectrometer leak detector.

[0199] Interface bonding strength test: Adopted the shear test method.

[0200] X-ray fluoroscopy inspection: Internal defect detection.

[0201] 4. Qualified rate statistics:

[0202] According to the product technical standards, count the number of qualified products and the qualified rate of each batch.

[0203] Conduct defect analysis on unqualified products to determine the failure causes.

[0204] 5. Inter-batch consistency analysis:

[0205] Randomly select 30 qualified products from each batch and measure their key performance indicators.

[0206] Calculate the average value and standard deviation of each performance indicator to evaluate the inter-batch consistency.

[0207] 6. Experimental results

[0208] Comparison of qualified rates:

[0209] The comparison results of the qualified rates of the products of the three processes are as Figure 12 shown:

[0210] From Figure 12 It can be seen that the qualified rate of the products in Batch C has increased by 9 percentage points compared with Batch A and by 5 percentage points compared with Batch B, reaching a high level of 96.0%. In particular, the unqualified situation caused by insufficient air tightness has been completely eliminated in Batch C, indicating that the pressure wave modulation forming method has a significant effect on controlling interface microbubbles.

[0211] Comparison of product defect distributions:

[0212] Figure 13 Shows the distribution of defect types of the products of the three processes:

[0213] The figure shows that during the production process of five consecutive batches, the fluctuation ranges of the bonding strength and airtightness of the products produced by the pressure wave modulation forming method are significantly smaller than those of the traditional hot pressing process and the ultrasonic-electric field synergistic process, indicating that this method can significantly improve the consistency between product batches and ensure the stability of product quality.

[0214] Based on the above experimental results, it can be seen that the pressure wave modulation forming method of the present invention significantly improves the consistency and yield rate of products. The yield rate is increased from 87.0% of the traditional process to 96.0%. The standard deviation of the key performance indicators is significantly reduced, and the performance fluctuation between product batches is significantly decreased, verifying the aforementioned technical effects.

[0215] Experiment Five: Verification of Application Range Expansion

[0216] 1. Experimental Purpose

[0217] Verify that the pressure wave modulation forming method can expand the application range of gradient silicon-aluminum electronic packaging materials in harsh environments.

[0218] 2. Experimental Steps

[0219] Sample Preparation:

[0220] Twenty gradient silicon-aluminum-titanium alloy composite packages of the same specification are prepared using three different processes respectively.

[0221] Group A: Using the traditional hot pressing forming process (control group).

[0222] Group B: Using the conventional ultrasonic-electric field synergistic process.

[0223] Group C: Using the pressure wave modulation forming method of the present invention.

[0224] 2. Extreme Environment Simulation Test:

[0225] High and low temperature alternating test: -65°C to +150°C, 500 cycles.

[0226] Damp heat test: 85°C / 85%RH, 1000 hours.

[0227] Salt spray test: 5% NaCl solution, 500 hours.

[0228] Simulated deep sea environment test: 20 MPa water pressure, 5°C, 500 hours.

[0229] Irradiation test: Total dose 1×10^6 rad(Si).

[0230] 3. Reliability Evaluation:

[0231] Before and after each environmental test, various performance detections are carried out, including airtightness, bonding strength, etc.

[0232] Calculate the computational performance retention rate to evaluate the reliability of different process samples in extreme environments.

[0233] 4. Application scenario adaptability analysis:

[0234] Analyze the adaptability of different process samples to various extreme environments based on the test results.

[0235] Determine the reliable service life under various application scenarios.

[0236] 5. Experimental results

[0237] Airtightness retention rate after extreme environment testing:

[0238] The airtightness retention rates of the three process samples after various extreme environment tests are as Figure 14 shown:

[0239] From Figure 14 it can be seen that the airtightness retention rates of Group C samples after various extreme environment tests are significantly higher than those of Group A and Group B. Especially after the simulated deep-sea environment test, the airtightness retention rate of Group C samples is 85.3%, while that of Group A is only 38.6%, indicating that the samples prepared by the pressure wave modulation forming method have higher reliability in extreme environments.

[0240] Bond strength retention rate after extreme environment testing:

[0241] The bond strength retention rates of the three process samples after various extreme environment tests are as Figure 15 shown:

[0242] From Figure 15 it can be seen that the bond strength retention rates of Group C samples after various extreme environment tests are significantly higher than those of Group A and Group B, indicating that the samples prepared by the pressure wave modulation forming method have better interface stability and long-term reliability.

[0243] Extreme environment adaptability comparison:

[0244] Figure 16 Shows the comprehensive performance retention rates (average retention rates of airtightness and bond strength) of the three process samples in different extreme environments:

[0245] This radar chart shows that the samples prepared by the pressure wave modulation forming method exhibit excellent performance retention rates in various extreme environments. Especially under harsh conditions such as deep-sea environment and humid and hot environment, the performance advantages are more significant, indicating that this method can effectively expand the application range of gradient silicon-aluminum electronic packaging materials.

[0246] Application scenario adaptability analysis:

[0247] According to the requirements of material properties for different application scenarios, the adaptability of the three process samples was analyzed, and the results are as Figure 17 shown:

[0248] From Figure 17 it can be seen that the samples prepared by the pressure wave modulation forming method can adapt to various application scenarios from ordinary industrial electronics to harsh environments such as deep-sea equipment and polar equipment, while the samples prepared by the traditional hot pressing process are only applicable to ordinary industrial electronics and some aerospace electronics fields, and the samples prepared by the ultrasonic-electric field synergistic process are not applicable to the deep-sea equipment field. This shows that the pressure wave modulation forming method of the present invention significantly expands the application range of the gradient silicon-aluminum electronic packaging material.

[0249] The embodiments of the present invention have been described above, but the embodiments are not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of this embodiment, those of ordinary skill in the art can also make more equivalent embodiments in various forms, all of which fall within the protection scope of this embodiment.

Claims

1. A method for forming a local gradient silicon-aluminum electronic packaging material, characterized in that: The following steps are involved: Step 1: Perform micro-nano structural pretreatment on the interface between the gradient silicon-aluminum material to be composited and the heterogeneous metal; Step 2: Determine the pressure wave frequency according to the ultrasonic frequency used, make the ratio of the pressure wave frequency to the ultrasonic frequency be 1:3 to 1:5, make and install the pressure wave source, build a pressure wave-ultrasonic wave synchronous control system, and synchronize the pressure wave peak with the ultrasonic cavitation negative pressure stage; Step 3: During the ultrasonic-electric field synergistic interface treatment process, periodic pressure wave intensity changes are performed, including a low intensity stage, a medium intensity stage, and a high intensity stage, while maintaining a stable output of ultrasonic waves and electric fields; Step 4: Place the composite material in a dedicated processing chamber and apply a triple physical field combination in a specific sequence, first applying an electric field, then applying ultrasonic waves while maintaining the electric field, and finally applying a pressure wave with an intensity gradient while maintaining the first two; Step 5: The processed materials are subjected to hot pressing and quality inspection.

2. A method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The micro-nano structure pretreatment in step 1 includes: mechanically roughening the surfaces of the gradient silicon-aluminum material and the heterogeneous metal to be composited to form a microscopic rough structure with a depth of 5-15 μm; chemically activating the material interface to remove surface oxides and impurities; and coating a special activator on the interface to be combined, with the activator coating thickness controlled within the range of 10-30 μm.

3. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The synchronous control system in step 2 achieves a phase difference control accuracy of no less than ±5° between the pressure wave and the ultrasonic wave.

4. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: In the periodic pressure wave intensity change pattern in step 3: the low intensity stage lasts 10-30 seconds, and the pressure wave amplitude is 30-50% of the baseline value; the medium intensity stage lasts 20-60 seconds, and the pressure wave amplitude is 60-80% of the baseline value; the high intensity stage lasts 5-15 seconds, and the pressure wave amplitude is 90-120% of the baseline value.

5. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The ultrasonic power density maintained in step 3 is 15-25 W / cm 2 , the electric field strength is 50-150V / mm.

6. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: In step 4, the duration of applying the electric field is 30-60 seconds, the duration of applying the ultrasonic wave is 60-120 seconds, and the duration of applying the pressure wave is 120-180 seconds.

7. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: In step 4, one side of the dedicated processing chamber is configured as a region with relatively weak pressure wave intensity, and the other side is configured as a region with relatively strong pressure wave intensity, forming a pressure wave intensity gradient from the outside to the inside of the interface.

8. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The step 4 also includes real-time monitoring of changes in acoustic properties of the interface region, and evaluating the extent and effect of bubble migration by analyzing acoustic response signals.

9. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The hot pressing molding in step 5 is carried out at a temperature of 450-550° C. and a pressure of 30-50 MPa, and the hot pressing time is 30-90 minutes.

10. The method for forming a local gradient silicon-aluminum electronic packaging material according to claim 1, characterized in that: The quality inspection in step 5 includes interface bonding strength test, air tightness test, interface microstructure analysis and thermal cycle test, wherein the air tightness test qualification standard is that the air tightness is not higher than 1×10^ -7 Pa·m 3 / s, the thermal cycle test was carried out in the temperature range of -55℃ to +125℃, and the number of cycles was 100-500 times.

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