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CN-121994739-A - Shear modulus testing method for polymer packaging material curing process

CN121994739ACN 121994739 ACN121994739 ACN 121994739ACN-121994739-A

Abstract

The invention relates to a shear modulus testing method in a curing process of a polymer packaging material, which comprises the following steps of 1, obtaining polymer conversion rate data at different moments and clear curing process temperature parameters through in-situ monitoring based on attenuated total reflection Fourier infrared spectra set by the curing process temperature parameters, 2, obtaining associated data of shear modulus and time through synchronous mechanical property testing based on the clear curing process temperature parameters in the step 1, and 3, obtaining corresponding polymer shear modulus under different conversion rates through multi-scale data fusion based on the conversion rate data in the step 1, the curing process temperature parameters and the shear modulus and time associated data in the step 2. The method has the advantages of high synchronism and accuracy, realizes full-period mechanical characterization, and provides scientific basis for internal stress prediction and demolding time determination in the composite material molding process.

Inventors

  • QIN HONGBO
  • Zhan Zhuangchao
  • WANG YUPENG
  • YANG DAOGUO
  • CAI MIAO
  • ZHONG SI

Assignees

  • 桂林电子科技大学

Dates

Publication Date
20260508
Application Date
20260121

Claims (7)

  1. 1. The shear modulus testing method for the curing process of the polymer packaging material is characterized by comprising the following steps of: step 1, obtaining polymer conversion rate data at different moments and clear curing process temperature parameters through in-situ monitoring based on attenuated total reflection Fourier infrared spectra set by the curing process temperature parameters; Step 2, based on the clear curing process temperature parameter of the step 1, obtaining the correlation data of the shear modulus and time through synchronous mechanical property test; And step 3, obtaining the corresponding polymer shear modulus under different conversion rates through multi-scale data fusion based on the conversion rate data of the step 1, the curing process temperature parameter and the shear modulus and time correlation data of the step 2.
  2. 2. The method for testing shear modulus during curing of a polymer encapsulating material according to claim 1, wherein step 1 specifically comprises: Step 1.1, accurately weighing a polymer and a curing agent according to a stoichiometric ratio, uniformly mixing in a vacuum stirrer to obtain a mixture and defoaming; Step 1.2, 10-20mg of the mixture is coated on the surface of the attenuated total reflection crystal, so that the central light path area of the crystal is completely covered; Step 1.3, setting a temperature change curve of a heating table according to the requirements of a curing process based on attenuated total reflection Fourier infrared spectrum equipped with a heating accessory, setting the spectral range to 600-4000 cm -1 , setting the resolution to 4 cm -1 , setting the scanning times of a single spectrogram to 16, 32 or 64 times according to the reaction rate, and selecting a series of acquisition or dynamic modes according to an acquisition mode, wherein the acquisition interval is 1 sheet every 1 minute; Step 1.4, firstly, collecting a background spectrum in an empty platform state to deduct the interference of water vapor and carbon dioxide in the air, then rapidly dripping a polymer to be detected, immediately collecting a first spectrogram as reference data of t=0, and starting an acquisition program to enable software to automatically record spectrograms at different time points; Step 1.5, after the attenuated total reflection Fourier infrared spectrum test is completed, carrying out baseline correction and integral processing on characteristic peaks by using software, and calculating conversion rates at different moments according to the following formula: ; ; Wherein, alpha t is the conversion rate at the time t, A t is the absorbance of the characteristic peak of the reaction at the time t, R t is the absorbance of the internal standard peak at the time t, A 0 and R 0 are the absorbance of the characteristic peak and the internal standard peak before the reaction starts, and A' is the absorbance ratio after normalization.
  3. 3. The method of claim 1, wherein if the mixture is a solid powder coating in step 1.2, the mixture is compressed and then coated on the surface of the attenuated total reflection crystal.
  4. 4. The method of claim 1, wherein the attenuated total reflection crystal in step 1.2 is a diamond or ZnSe crystal.
  5. 5. The method for testing shear modulus during curing of a polymer encapsulating material according to claim 1, wherein step 2 specifically comprises: step 2.1, preparing a customized die, and clamping an upper die and a lower die of the die in the vertical direction by using a stretching clamp in a dynamic mechanical analyzer or a universal testing machine with a temperature box; 2.2, injecting a preset amount of polymer to be detected into a cavity of the die by using a pipetting needle, so that the polymer to be detected forms a circular ring shape in the cavity of the die, and taking the temperature change parameters of the curing process which are defined in the step 1: if a dynamic mode is adopted, setting the frequency to be 1 Hz, applying a fixed sinusoidal strain amplitude of 0.1%, and directly acquiring the relationship between the shear storage modulus and time after starting a test; If a constant speed rate mode is adopted, setting the displacement rate to be 1% strain/min, starting a test at a key time point of the corresponding conversion rate determined in the step 1, recording the shearing force F perpendicular to the cross section and the displacement deltax of the movable clamp, and calculating to obtain the shearing modulus G through the following formula: ; ; ; Wherein τ is shear stress, A is the area of the stress surface, γ is shear strain, θ is shear angle, Δx is displacement of the movable clamp, and h is the radius of the ring-shaped polymer to be measured.
  6. 6. The method of claim 5, wherein the mold in step 2 is made of polytetrafluoroethylene.
  7. 7. The method according to any one of claims 1 to 6, wherein step 3 is specifically: And (3) taking a time axis as an intermediary, accurately aligning the conversion rate data at different moments, the clear curing process temperature parameters and the related data of the shear modulus and time obtained in the step (2), constructing a four-dimensional mapping relation model of the curing temperature, the time, the conversion rate and the shear modulus, and directly inquiring or deducing the corresponding shear modulus under the specific conversion rate through the model.

Description

Shear modulus testing method for polymer packaging material curing process Technical Field The invention belongs to the field of polymer shear modulus testing, and particularly relates to a shear modulus testing method in a curing process of a polymer packaging material. Background In advanced packaging technology for semiconductors, polymer packaging materials play a key role in mechanical support and environmental and protection. Unlike macroscopic structural components that are primarily subjected to tensile and compressive loads, the core challenge of the package structure is thermal mismatch of the multi-layer heterogeneous material interfaces. Because of the large difference in thermal expansion coefficients of the chip, the substrate and the polymer packaging material, severe shear stress can be generated at the contact interface in the processes of solidification and cooling and subsequent thermal cycling. Shear modulus is a core parameter that measures the ability of a material to resist shear deformation (i.e., change in shape without changing volume). In package reliability analysis, the shear modulus directly determines the shear failure force exerted by the polymer on the solder joints and the rewiring layer during thermal expansion and contraction. Once the shear modulus evolution and stress release mechanism during curing are unbalanced, interfacial delamination, corner cracking, and solder ball shear fatigue failure are very likely to result. Therefore, accurate acquisition of shear modulus data for the full cure cycle is a precondition for building a high-precision finite element simulation model to predict warpage and fatigue life. Accurate measurement of shear modulus during polymer curing faces the great technical challenges of "trans-scale" and "abrupt phase change", and the existing test means have obvious measurement dead zones. The first method is the rotary rheometer test, which is currently the mainstream method for testing rheological properties of liquid and gel polymers, by applying a shear flow field through a parallel plate or cone plate clamp. When the polymer is solidified into a high modulus stage (glassy state), the material is hardened and contracted, wall surface sliding or interfacial debonding is easy to occur on the surface of the test fixture, so that the measured modulus value is far lower than a true value, and meanwhile, the flexibility of the instrument can generate obvious errors when testing hard solids. The second method is a shear/torsion mode of dynamic thermo-mechanical analysis, which is applicable to solid splines that have been fully cured. The method cannot process the initial liquid polymer (cannot mold and clamp), so that a shear modulus evolution curve of a complete continuous process from liquid-gel point-solid state cannot be obtained, and data of the most critical gelation transition stage for generating residual stress is lost. The third method is an ultrasonic reflection method, and the shear modulus is calculated based on the propagation velocity of the transverse wave. The transverse wave decays very fast in liquid and viscous medium, resulting in weak signal and low signal-to-noise ratio in the initial stage of solidification, and difficult to realize accurate monitoring of the whole process. In summary, the traditional macroscopic mechanical test is mainly aimed at static tensile elastic modulus, and can not characterize pure shear behavior of materials, while the rheology and thermal analysis methods are respectively limited to "soft" fluid or "hard" solid, and lack a shear modulus test method capable of continuously and precisely passing through the whole process of polymer transition from low-viscosity liquid to high-modulus solid without slippage. The lack of testing capability severely restricts the deep understanding and accurate control of advanced packaging material curing dynamics and residual shear stress evolution. Disclosure of Invention In summary, the technical problem to be solved by the invention is to provide a shear modulus testing method for a curing process of a polymer packaging material, which solves the technical problem that the traditional curing monitoring of the polymer packaging material often faces the problem of dislocation of microscopic chemical reaction and macroscopic mechanical property evolution. First, the test conditions are inconsistent. Previous studies have often measured conversion and modulus separately at different equipment and different temperature programs, resulting in poor data matching. Second, the whole curing process is difficult to cover. Common shear testing has difficulty in achieving full-scale monitoring from the initial liquid state to the hardened solid state. Third, there is a lack of quantitative association models. It is difficult to accurately determine the exact value of the corresponding shear modulus at a specific conversion (degree of cure), resulting in lack of mechanical cr