Resonant Acoustic Frequency Shifts Associated With Cracks in Multilayer Ceramic Capacitors

Johnson, Ward L.; Herzberger, Jaemi; Kim, Sudook A.; Peterson, Kirsten L.; Heyliger, Paul R.; White, Grady S.

doi:10.1109/tdmr.2017.2682818

Cited by 8 publications

(5 citation statements)

References 12 publications

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“…Recently, it was shown that a narrow-pulse frequency sweep signal can be used to produce vibration in MLCCs, and that bending the circuit board in order to produce cracks in the MLCCs changes the acoustic emission characteristics of the capacitors [18]. Similar findings have been made by Johnson et al using resonant ultrasound spectroscopy [19]- [21]. The acoustic approach is particularly interesting, since there is a need in the industry for a method that could identify damaged capacitors from an assembled board.…”

supporting

confidence: 59%

Acoustic Detection of Cracks and Delamination in Multilayer Ceramic Capacitors

Levikari

Kärkkäinen

Andersson

et al. 2019

IEEE Trans. on Ind. Applicat.

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Multilayer ceramic capacitors (MLCC) are the most widely used capacitor type in the electronics industry. However, the brittle ceramic dielectric makes MLCCs prone to mechanical damage. Manufacturing defects or damage during board assembly may cause a capacitor to prematurely fail during its operational life. Here, we demonstrate the fast and non-destructive acoustic screening of MLCCs. Soldered 2220-sized MLCCs were subjected to ac voltage frequency sweeps, causing them to vibrate mechanically. Acoustic responses of the capacitors were measured before and after subjecting the test circuit board to severe bending. The results show that the cracks and delaminations caused by bending induce characteristic changes in the capacitors' acoustic response. A support vector machine classifier was trained to successfully detect damaged capacitors based on their acoustic response. Index Terms-Acoustic emission, ceramic capacitors, nondestructive testing. I. INTRODUCTION M ULTILAYER ceramic capacitors (MLCCs) are commonly used in the electronics industry [1]. The ceramic dielectric gives MLCCs high capacitance per volume, but also makes them prone to mechanical damage. Voids and delaminations are typical manufacturing defects in MLCCs, often related to thermal stresses [2], [3]. Mechanical stress, such as improper printed circuit board (PCB) handling during assembly, can lead to cracks or delamination in MLCCs [4], [5]. Mechanical damage in MLCCs is often left unrecognized during production or assembly, as the capacitor may operate normally electrically. However, in the field, a crack or delamination in an MLCC may grow in size, resulting in loss of Manuscript

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supporting

confidence: 59%

Acoustic Detection of Cracks and Delamination in Multilayer Ceramic Capacitors

Levikari

Kärkkäinen

Andersson

et al. 2019

IEEE Trans. on Ind. Applicat.

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“…exhibited a significant degree of the subharmonic terms. The occurrence of the subharmonics could be produced by the nonlinear characteristic of the elasticity in the damaged MLCC structure [14][15]. Meanwhile, for the actual MLCC data, we could also observe the reduced level of the peak signal in the WIF(Ω) that was not found in the simulation result.…”

Section: Test Resultsmentioning

confidence: 75%

“…Yet, the conventional methods *howuk@inha.ac.kr; phone 82 032 860-7317; fax 82 032 868-1716; https://a2sp.inha.ac.kr In contrast, electromechanical (EM) methods leverage the piezoelectric properties of BTO in MLCCs for instant damage detection in a nondestructive manner. The nondestructive EM method utilizes tone-burst voltage excitation and refers to transient EM response in MLCC after the tone-burst actuation [14]. Typical approaches classify the structural status of MLCCs using the resonance frequency or the phase variation at the resonance frequency in the tone-burst test [15][16].…”

Section: Introductionmentioning

confidence: 99%

Micro-size damage detection of multilayer ceramic capacitors based on Hilbert-Huang transform of electromechanical responses

Na,

Lee,

Choi

et al. 2024

Health Monitoring of Structural and Biological Systems XVIII

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This study aims to detect micro defects in multilayer ceramic capacitors (MLCC) using a new signal processing method for electromechanical (EM) responses. Microscopic defects within MLCC structures, not screened during the manufacturing production stage, can cause damage to electronic products and further lead to overall system failure. Therefore, it is very important to secure reliable defect detection technology. However, conventional methods, such as X-ray and ultrasound tests, are destructive, cost-ineffective, and inaccurate. In this study, we applied a new signal processing method based on the Hilbert-Huang transform (HHT) of the EM response for the nondestructive screening of MLCCs with hidden defects. We first observed that infinitesimal, irregular oscillation in the instantaneous frequency in the transient response when the MLCC had defects. Therefore, we introduced a new signal processing method that takes the Fourier transform (FT) of the weightedinstantaneous frequency (WIF) concerning the frequency-oscillatory rate, to capture the infinitesimal change in the HHT signal. Specifically, we confirmed that subharmonic terms, possibly caused by the nonlinear effect, arose in the WIF when the target MLCC had a micro defect. The method was first validated through signals obtained from transient finite element analysis, followed by a comparison with the test data from actual MLCCs. The increased subharmonic terms in the WIF could be an effective indication of the defect in the MLCC. This study will provide a new methodology for detecting microdefects in MLCC.

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“…This phenomenon arises from the piezoelectric properties of the ceramic dielectric, making the capacitor body physically vibrate as the ceramic material deforms under an AC field [18]. To date, there are several studies about observing cracks in the ceramic body of an MLCC by changes in its resonant behavior [19]- [21]. These experiments are mainly based on ferroelectric transduction, where a DC-biased MLCC is excited using short radio frequency tone bursts, and the decay of the MLCC "ringing" after the burst is observed.…”

Section: B Acoustic Emissions In Mlccsmentioning

confidence: 99%

“…Based on these conditions, eight numerical features shown in Table 2 were extracted for each MLCC. The resonant peak amplitudes A 1 and A 2 along with their corresponding resonance frequencies f 1 and f 2 were chosen, as past studies [20], [21], [23] have suggested that these resonance peaks might indicate the presence of damage. However, especially A 1 and A 2 displayed notable systematic differences between two intact PCBs, probably related to external factors such as the level of ambient EMI, as the two boards were characterized on different occasions.…”

Section: B Preprocessing Of Acoustic Datamentioning

confidence: 99%