A method for monitoring the consolidation behavior of conductive silver paste
By establishing a molecular dynamics model of conductive silver paste, simulating the consolidation process, and monitoring the movement changes of conductive silver paste atoms, the problem of inability to monitor the consolidation behavior of conductive silver paste in real time in the existing technology is solved, real-time monitoring and optimization are achieved, and cost is reduced.
Patent Information
- Application Number
- CN202110847561.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-07-27
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2041-07-27
AI Technical Summary
The prior art cannot monitor the consolidation behavior in real time during the consolidation process of conductive silver paste, resulting in low production efficiency and high cost, making it difficult to achieve rapid iteration and optimization.
By establishing a molecular dynamics model of conductive silver paste, the consolidation process is simulated, the movement changes of the conductive silver paste as a whole and various types of atoms are monitored, and the consolidation behavior is tracked in real time.
Real-time monitoring of the consolidation behavior of conductive silver paste is achieved, the R&D costs are reduced, the forming parameters are optimized, and theoretical guidance is provided for scientific research and industrial production.
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Figure CN113591296B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of electronic circuit manufacturing and relates to a method for monitoring the consolidation behavior of conductive silver paste. Background Art
[0002] The consolidation effect of conductive silver paste has a decisive influence on the performance of the manufactured conductive circuit (such as resistivity, morphology, size, etc.). During the consolidation process of conductive silver paste, there are complex physical and chemical phenomena inside, which can be generally divided into three types of reaction behaviors: silver particle fusion, organic matter removal, and solvent volatilization, which jointly determine the consolidation effect of conductive silver paste. Therefore, monitoring the consolidation behavior of conductive silver paste is a necessary means to control the consolidation effect of conductive silver paste.
[0003] At present, the analysis of the above-mentioned consolidation behavior of conductive silver paste cannot be realized in real time during the consolidation process. The main method is to compare the physical phase analysis before and after the consolidation of the conductive silver paste and infer the consolidation behavior of the conductive silver paste during the consolidation process. This method is time-consuming and costly, which is not conducive to the rapid iteration and optimization of electronic circuit production. Summary of the invention
[0004] In view of the problems pointed out in the above background technology, the present invention proposes a method for monitoring the consolidation behavior of conductive silver paste.
[0005] The technical solution adopted by the present invention is:
[0006] A method for monitoring the consolidation behavior of a conductive silver paste comprises the following steps:
[0007] Step 1: Establish a molecular dynamics model of the conductive silver paste, import it into the molecular dynamics software and perform initialization settings; classify and mark the conductive silver paste atoms;
[0008] Step 2: setting the conductive silver paste consolidation control parameters to simulate the conductive silver paste consolidation process;
[0009] Step 3: Extract the movement changes of the conductive silver paste as a whole and various types of atoms during the consolidation process, and monitor the consolidation behavior of the conductive silver paste.
[0010] Furthermore, in step one, the conductive silver paste atoms are classified according to different systems, including silver particles, solvents, organic matter and other four categories.
[0011] Furthermore, in step 2, the conductive silver paste consolidation control parameters include: force field control parameters, which are used to describe the forces between atoms in the system; and temperature control parameters, which are used to describe the change mode of the conductive silver paste consolidation temperature.
[0012] Furthermore, in step 2, during the simulation of the consolidation of the conductive silver paste, as the applied temperature changes, the forces between atoms in the system change, and the atoms move, thereby describing the physicochemical reactions occurring during the consolidation of the conductive silver paste; the physicochemical reactions include volatilization of the conductive silver paste solvent, removal of organic matter, and fusion of silver particles.
[0013] Furthermore, the organic matter removal includes organic matter desorption and organic matter decomposition.
[0014] Furthermore, in step three, the method for monitoring the desorption behavior of organic matter during the consolidation process of the conductive silver paste is specifically as follows: define the critical distance b for the effective coating of silver particles by organic matter, and count the distance between the organic matter molecules and the atoms on the surface of the silver particles during the consolidation process; if the distance is less than or equal to b, it is regarded as an organic adsorption state; if the distance is greater than b, it is regarded as an organic desorption state; the process in which the distance between the organic matter molecules and the surface of the silver particles changes from less than b to greater than b is the organic desorption process.
[0015] Furthermore, in step three, the method for monitoring the decomposition behavior of organic matter during the consolidation process of the conductive silver paste is specifically as follows: statistically analyzing the positions and movement trajectories of all organic atoms during the consolidation process, judging the bonding conditions between atoms by the relative positions of the atoms, and thus analyzing the decomposition products; at the same time, judging the product state in combination with the temperature conditions.
[0016] Furthermore, in step three, the method for monitoring the solvent volatilization behavior during the consolidation process of the conductive silver paste is specifically as follows: for a specific solvent, a critical distance a between gas-liquid molecules is defined, and the distance between solvent molecules during the consolidation process is counted. If the distance is less than or equal to a, it is regarded as a liquid; if the distance is greater than a, it is regarded as a gas; the process in which the distance between solvent molecules changes from less than a to greater than a is the solvent volatilization behavior.
[0017] Furthermore, in step three, the method for monitoring the fusion behavior of silver particles during the consolidation process of the conductive silver paste is specifically as follows: dividing a certain area between the silver particles, calculating the coordinate difference between the upper and lower boundaries of the silver atoms in the area during the consolidation process, and the difference is the fusion sintering neck width of the silver particles; judging the fusion status of the silver particles by the sintering neck width.
[0018] The beneficial effects of the present invention are:
[0019] The present invention monitors the consolidation behavior of the conductive silver paste by establishing a conductive silver paste consolidation model. First, based on experimental facts, the conductive silver paste model atoms are classified according to their functions inside the conductive silver paste, so that the solvent volatilization, organic matter removal and silver particle fusion occurring during the conductive silver paste consolidation process can be well described. Secondly, the real-time tracking of the movement trajectories of all atoms inside the conductive silver paste can be used to quantitatively and qualitatively analyze the physical and chemical reactions occurring during the entire conductive silver paste consolidation process.
[0020] The present invention can evaluate the reliability of the solution, assist in clarifying the consolidation principle of the conductive silver paste, reduce R&D costs, optimize forming parameters, and provide theoretical guidance for scientific research and industrial production, with respect to the difficulties that the current consolidation behavior of the conductive silver paste cannot be monitored in real time through experiments and the phase analysis method of comparing before and after the experiment is time-consuming and costly. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a visualization diagram of the conductive silver paste model in an embodiment of the present invention;
[0022] Figure 2 This is a visualization diagram of the volatilization trajectory of the conductive silver paste heated solvent in an embodiment of the present invention;
[0023] Figure 3 This is a visualization diagram of the melting of silver particles by heating the conductive silver paste in an embodiment of the present invention. DETAILED DESCRIPTION
[0024] The present invention is a million-level atom simulation prediction technology for the conductive silver paste consolidation process, which monitors the conductive silver paste consolidation behavior through large-scale atomic motion simulation.
[0025] The conductive silver paste consolidation behavior monitoring method of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0026] A method for monitoring the consolidation behavior of a conductive silver paste comprises the following steps:
[0027] Step 1: Establish a molecular dynamics model of the conductive silver paste, import it into the molecular dynamics software and perform initialization settings. Classify and mark the conductive silver paste atoms.
[0028] Specifically, the conductive silver paste atoms are classified according to different systems, including silver particles, solvents, organic matter and other four categories.
[0029] Step 2: Set the conductive silver paste consolidation control parameters to simulate the conductive silver paste consolidation process.
[0030] The conductive silver paste consolidation control parameters include: force field control parameters, which are used to describe the forces between atoms in the system, and temperature control parameters, which are used to describe the change of the conductive silver paste consolidation temperature.
[0031] During the simulation of conductive silver paste consolidation, as the applied temperature changes, the forces between atoms in the system change and the atoms move, thus describing the physical and chemical reactions that occur during the consolidation of the conductive silver paste. The physical and chemical reactions include the volatilization of the conductive silver paste solvent, the removal of organic matter, and the fusion of silver particles. The removal of organic matter includes the desorption and decomposition of organic matter.
[0032] Step 3: Extract the movement changes of the conductive silver paste as a whole and various types of atoms during the consolidation process, and monitor the consolidation behavior of the conductive silver paste.
[0033] The method for monitoring the desorption behavior of organic matter during the consolidation of conductive silver paste is as follows: define the critical distance b for the organic matter to effectively cover the silver particles, and count the distance between the organic matter molecules and the atoms on the surface of the silver particles during the consolidation process. If the distance is less than or equal to b, it is considered to be in the organic matter adsorption state. If the distance is greater than b, it is considered to be in the organic matter desorption state. The process in which the distance between the organic matter molecules and the surface of the silver particles changes from less than b to greater than b is the organic matter desorption process.
[0034] The method for monitoring the decomposition behavior of organic matter during the consolidation process of conductive silver paste is as follows: the positions and movement trajectories of all organic atoms in the consolidation process are counted, the bonding conditions between atoms are determined by the relative positions of atoms, and the decomposition products are analyzed. At the same time, the product state is determined in combination with the temperature conditions.
[0035] The method for monitoring the solvent volatilization during the consolidation of the conductive silver paste is as follows: for a specific solvent, define the critical distance a between gas and liquid molecules, and count the distance between solvent molecules during the consolidation process. If the distance is less than or equal to a, it is considered to be liquid. If the distance is greater than a, it is considered to be gaseous. The process in which the distance between solvent molecules changes from less than a to greater than a is the solvent volatilization behavior.
[0036] The method for monitoring the fusion behavior of silver particles during the consolidation of conductive silver paste is as follows: a certain area between silver particles is divided, and the coordinate difference between the upper and lower boundaries of the silver atoms in the area during the consolidation process is calculated. The difference is the width of the fusion sintering neck of the silver particles. The fusion of silver particles is judged by the sintering neck width.
[0037] The following takes a certain type A conductive silver paste heated at 600° C. for 200 ps as an example to exemplify the technical solution of the present invention.
[0038] Step 1: Establish a molecular dynamics model of the conductive silver paste, import it into a molecular dynamics software (such as LAMMPS) and perform initialization settings. Classify and label the conductive silver paste atoms.
[0039] Establish a molecular dynamics model of conductive silver paste. According to the experimental test results of a certain type A conductive silver paste, a conductive silver paste model that matches it is established, including solvent water, organic PAA and nanosilver particles with a diameter of 4nm. First, bare nanosilver particles with a diameter of 4nm are established, and then 20 PAA polymer molecules with a molecular weight of 1440 are randomly distributed on the surface of the nanosilver particles to obtain an organic-coated nanosilver particle model. Arrange 8 organic-coated nanosilver particle models in space in a 2×2×2 distribution pattern, with a spacing of 0.2nm between each other, to obtain a nanosilver particle cluster model. Place the cluster model in a 10nm×10nm×10nm water box to obtain a molecular dynamics model of the nanosilver paste, as shown in the visualization diagram. Figure 1 shown.
[0040] Import the conductive silver paste molecular dynamics model into the molecular dynamics software and perform initialization settings. According to the format requirements of the molecular dynamics software for the model file, save the established conductive silver paste molecular dynamics model as a .data file that meets the requirements and import it into the molecular dynamics software LAMMPS. Perform initialization settings for the simulation, as shown in Table 1.
[0041] Table 1 Simulation initialization parameter settings
[0042]
[0043] The conductive silver paste atoms are classified and labeled. According to the model settings, there are 6 types of atoms, namely type 1H (H atoms in water molecules), type 2O (O atoms in water molecules), type 3Ag (Ag atoms in silver particles), type 4C (C atoms in PAA molecules), type 5H (H atoms in PAA molecules), and type 6O (O atoms in PAA molecules).
[0044] According to different atomic systems, atoms are divided into three categories, namely group Water type 1 2 (representing water molecules), group Ag type 3 (representing nanosilver particles), and group PAA type 4 5 6 (representing PAA molecules).
[0045] Step 2: Set the conductive silver paste consolidation control parameters to simulate the conductive silver paste consolidation process.
[0046] Set the conductive silver paste consolidation control parameters, including force field control parameters and temperature control parameters. For the force field control parameters of this embodiment, the force field type used to describe the atomic forces within the PAA molecule is reax / c, the force field type used to describe the atomic forces within the water molecule is lj / cut / coul / long, the force field type used to describe the silver atomic forces within the silver particles is EAM, and the force field type used to describe the interaction forces between PAA molecules, water molecules and silver particles is lj / cut / coul / long. For the temperature control parameters of this embodiment, the temperature control mode is NPT, the pressure is set to a constant 1 atmosphere, the temperature is set to relax for 100ps at 25°C, heat for 200ps every 100°C to reach 600°C, heat for 200ps at 600°C, cool for 200ps to 25°C, and relax for 100ps at 25°C. Set the simulation step size to 0.001ps to perform a conductive silver paste consolidation simulation.
[0047] Step 3: Extract the movement changes of the conductive silver paste as a whole and each type of atoms during the consolidation process, and monitor the consolidation behavior of the conductive silver paste. The specific method is:
[0048] Extract the movement changes of the conductive silver paste as a whole and each type of atoms during the consolidation process. Extract the movement trajectory of group Water atoms, monitor the evaporation of solvents, and visualize the evaporation process of solvents. Figure 2 As shown in the figure, the diffusion of water molecules indicates that the solvent has evaporated. The atomic motion trajectories of group PAA are extracted to monitor the decomposition behavior of organic matter. The atomic motion trajectories of group Ag are extracted to monitor the fusion behavior of silver particles, such as Figure 3 As shown. The motion trajectories of all atoms are extracted to monitor the consolidation behavior of the conductive silver paste.
[0049] It should be pointed out that the control parameters of the conductive silver paste consolidation force field in the present invention are prior art.
[0050] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the principles and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.
Claims
1. A method for monitoring the consolidation behavior of a conductive silver paste, characterized in that: The steps include: Step 1: Establish a molecular dynamics model of the conductive silver paste, import it into the molecular dynamics software and perform initialization settings; classify and mark the conductive silver paste atoms; Step 2: setting the conductive silver paste consolidation control parameters to simulate the conductive silver paste consolidation process; the conductive silver paste consolidation control parameters include: force field control parameters, which are used to describe the forces between atoms in the system; and temperature control parameters, which are used to describe the change mode of the conductive silver paste consolidation temperature; Step three, extract the movement changes of the conductive silver paste as a whole and various types of atoms during the consolidation process, and monitor the consolidation behavior of the conductive silver paste; in step three, the method for monitoring the desorption behavior of organic matter during the consolidation process of the conductive silver paste is specifically as follows: define the critical distance b for the effective coating of silver particles by organic matter, and count the distance between the organic molecules and the atoms on the surface of the silver particles during the consolidation process. If the distance is less than or equal to b, it is regarded as an organic adsorption state; if the distance is greater than b, it is regarded as an organic desorption state; the process in which the distance of the organic molecules relative to the surface of the silver particles changes from less than b to greater than b is the organic desorption process; the method for monitoring the decomposition behavior of organic matter during the consolidation process of the conductive silver paste is specifically as follows: count the positions and movement trajectories of all organic atoms during the consolidation process, judge the bonding situation between atoms by the relative positions of atoms, and thus analyze the decomposition products; at the same time, judge the product state in combination with the temperature conditions.
2. The method for monitoring the consolidation behavior of conductive silver paste according to claim 1, characterized in that: In step one, the conductive silver paste atoms are classified according to different systems, including silver particles, solvents, organic matter and other four categories.
3. The method for monitoring the consolidation behavior of conductive silver paste according to claim 1, characterized in that: In step 2, during the simulation of the consolidation of the conductive silver paste, as the applied temperature changes, the forces between atoms in the system change, and the atoms move, thereby describing the physicochemical reactions occurring during the consolidation of the conductive silver paste; the physicochemical reactions include the volatilization of the conductive silver paste solvent, the removal of organic matter, and the fusion of silver particles.
4. The method for monitoring the consolidation behavior of conductive silver paste according to claim 3, characterized in that: The organic matter removal includes organic matter desorption and organic matter decomposition.
5. The method for monitoring the consolidation behavior of conductive silver paste according to claim 4, characterized in that: In step three, the method for monitoring the evaporation of the solvent during the consolidation process of the conductive silver paste is specifically as follows: for a specific solvent, a critical distance a between gas-liquid molecules is defined, and the distance between solvent molecules during the consolidation process is counted. If the distance is less than or equal to a, it is regarded as a liquid; if the distance is greater than a, it is regarded as a gas; the process in which the distance between solvent molecules changes from less than a to greater than a is the evaporation of the solvent.
6. The method for monitoring the consolidation behavior of conductive silver paste according to claim 4, characterized in that: In step three, the method for monitoring the fusion behavior of silver particles during the consolidation process of the conductive silver paste is specifically as follows: dividing a certain area between the silver particles, calculating the coordinate difference between the upper and lower boundaries of the silver atoms in the area during the consolidation process, and the difference is the width of the fusion sintering neck of the silver particles; judging the fusion status of the silver particles by the sintering neck width.