FEM Simulation of cracks in MLCC during reflow soldering

Ahmar, Joseph Al; Wiese, S.

doi:10.1109/eurosime.2017.7926257

Cited by 12 publications

(7 citation statements)

References 4 publications

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“…Multilayered ceramic capacitor (MLCC) is an integral element of various electronic devices comprising a ceramic body with inner nickel electrodes and copper-based termination. The MLCC construction applies polymeric adhesives, such as Cu-epoxy resin, which are typically moisture-absorbent (Ahmar and Wiese, 2017; Chew et al , 2004). The absorbed moisture will vaporize during thermal reflow, inducing stress higher than the adhesion strength of the adhesive/substrate interface.…”

Section: Introductionmentioning

confidence: 99%

Deformation and crack growth in multilayered ceramic capacitor during thermal reflow process: numerical and experimental investigation

Apalowo,

Abas,

Bachok

et al. 2024

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Purpose This study aims to investigate the possible defects and their root causes in a soft-termination multilayered ceramic capacitor (MLCC) when subjected to a thermal reflow process. Design/methodology/approach Specimens of the capacitor assembly were subjected to JEDEC level 1 preconditioning (85 °C/85%RH/168 h) with 5× reflow at 270°C peak temperature. Then, they were inspected using a 2 µm scanning electron microscope to investigate the evidence of defects. The reliability test was also numerically simulated and analyzed using the extended finite element method implemented in ABAQUS. Findings Excellent agreements were observed between the SEM inspections and the simulation results. The findings showed evidence of discontinuities along the Cu and the Cu-epoxy layers and interfacial delamination crack at the Cu/Cu-epoxy interface. The possible root causes are thermal mismatch between the Cu and Cu-epoxy layers, moisture contamination and weak Cu/Cu-epoxy interface. The maximum crack length observed in the experimentally reflowed capacitor was measured as 75 µm, a 2.59% difference compared to the numerical prediction of 77.2 µm. Practical implications This work's contribution is expected to reduce the additional manufacturing cost and lead time in investigating reliability issues in MLCCs. Originality/value Despite the significant number of works on the reliability assessment of surface mount capacitors, work on crack growth in soft-termination MLCC is limited. Also, the combined experimental and numerical investigation of reflow-induced reliability issues in soft-termination MLCC is limited. These cited gaps are the novelties of this study.

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Section: Introductionmentioning

confidence: 99%

Deformation and crack growth in multilayered ceramic capacitor during thermal reflow process: numerical and experimental investigation

Apalowo,

Abas,

Bachok

et al. 2024

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“…Regardless, there are only a few simulations and experimental works on MLCC. Ahmar studied cracks in soldered MLCC using a four-point bending arrangement and an ANSYS finite element model for the capacitor (Ahmar et al , 2018; Ahmar and Wiese, 2015, 2017; Al Ahmar and Wiese, 2014). Krieger characterised MLCC cracks using electrical parameter testing, acoustic spectroscopy, impedance analysis and piezoelectric spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Investigation of moisture-induced crack propagation in the soft-termination multi-layer ceramic capacitor during thermal reflow process

Bachok,

Abas,

Raja Gobal

et al. 2023

SSMT

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Purpose This study aims to investigate crack propagation in a moisture-preconditioned soft-termination multi-layer ceramic capacitor (MLCC) during thermal reflow process. Design/methodology/approach Experimental and extended finite element method (X-FEM) numerical analyses were used to analyse the soft-termination MLCC during thermal reflow. A cross-sectional field emission scanning electron microscope image of an actual MLCC’s crack was used to validate the accuracy of the simulation results generated in the study. Findings At 270°C, micro-voids between the copper-electrode and copper-epoxy layers absorbed 284.2 mm/mg3 of moisture, which generated 6.29 MPa of vapour pressure and caused a crack to propagate. Moisture that rapidly vaporises during reflow can cause stresses that exceed the adhesive/substrate interface’s adhesion strength of 6 MPa. Higher vapour pressure reduces crack development resistance. Thus, the maximum crack propagation between the copper-electrode and copper-epoxy layers at high reflow temperature was 0.077 mm. The numerical model was well-validated, as the maximum crack propagation discrepancy was 2.6%. Practical implications This research holds significant implications for the industry by providing valuable insights into the moisture-induced crack propagation mechanisms in soft-termination MLCCs during the reflow process. The findings can be used to optimise the design, manufacturing and assembly processes, ultimately leading to enhanced product quality, improved performance and increased reliability in various electronic applications. Moreover, while the study focused on a specific type of soft-termination MLCC in the reflow process, the methodologies and principles used in this research can be extended to other types of MLCC packages. The fundamental understanding gained from this study can be extrapolated to similar structures, enabling manufacturers to implement effective strategies for crack reduction across a wider range of MLCC applications. Originality/value The moisture-induced crack propagation in the soft-termination MLCC during thermal reflow process has not been reported to date. X-FEM numerical analysis on crack propagation have never been researched on the soft-termination MLCC.

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“…The surface-mounted multi-layer ceramic capacitor (MLCC) is a common component in electronic assemblies and devices. Nonetheless, the undesired defects of MLCC, for instance voiding, cracking and delamination, significantly affect the functionality, reliability and lifespan of the device (Ahmar and Wiese, 2017). These structural impairments on the MLCC are caused by thermo-mechanical stresses encountered in the manufacturing, or due to the component processing during the handling and assembly stages (Malzbender, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…The parameter optimizations on reflow soldering were reported by using computational means (Tsai, 2012; Chen et al , 2016; Li et al , 2019). Nonetheless, the specific simulation works on the reflow of MLCCs are scarce in number, with only two being reported (Haslinda et al , 2017; Ahmar and Wiese, 2017). On the experimental approach, the effects of post-process parameters on crack propagation were studied by Park et al (2005) and Kang et al (2008).…”

Section: Introductionmentioning

confidence: 99%

“…There are other experimental works that studied the reflow soldering process of surface-mounted ceramic capacitors (Seppälä et al , 2000; Jin Kim et al , 2007; Tao et al , 2017), but without emphasizing the issues of cracking and delamination. To date, there is only one study that numerically simulates the crack in MLCCs during the reflow process (Ahmar and Wiese, 2017). It was inferred that the delamination issues in MLCCs receive less attention, while the numerical simulation methodology is perceived less well compared to its experimental counterpart.…”

Section: Introductionmentioning

confidence: 99%

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Numerical modelling of the delamination in multi-layered ceramic capacitor during the thermal reflow process

Abas

Ramli³

et al. 2022

SSMT

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Purpose This paper aims to study the interfacial delamination found in the boundary of the copper/copper-epoxy layers of a multi-layer ceramic capacitor. Design/methodology/approach The thermal reflow process of the capacitor assembly and the crack propagation from the initial micro voids presented in the boundary, and later manifested into delamination, were numerically simulated. Besides, the cross section of the capacitor assembly was inspected for delamination cracks and voids using a scanning electronic microscope. Findings Interfacial delamination in the boundary of copper/copper-epoxy layers was caused by the thermal mismatch and growth of micro voids during the thermal reflow process. The maximum deformation on the capacitor during reflow was 2.370 µm. It was found that a larger void would induce higher vicinity stress, mode I stress intensity factor, and crack elongation rate. Moreover, the crack extension increased with the exerted deformation until 0.3 µm, before saturating at the peak crack extension of around 0.078 µm. Practical implications The root cause of interfacial delamination issues in capacitors due to thermal reflow has been identified, and viable solutions proposed. These can eliminate the additional manufacturing cost and lead time incurred in identifying and tackling the issues; as well as benefit end-users, by promoting the electronic device reliability and performance. Originality/value To the best of the authors’ knowledge, the mechanism of delamination occurrence in a capacitor during has not been reported to date. The parametric variation analysis of the void size and deformation on the crack growth has never been conducted.

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FEM Simulation of cracks in MLCC during reflow soldering

Cited by 12 publications

References 4 publications

Deformation and crack growth in multilayered ceramic capacitor during thermal reflow process: numerical and experimental investigation

Deformation and crack growth in multilayered ceramic capacitor during thermal reflow process: numerical and experimental investigation

Investigation of moisture-induced crack propagation in the soft-termination multi-layer ceramic capacitor during thermal reflow process

Numerical modelling of the delamination in multi-layered ceramic capacitor during the thermal reflow process

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