by Liao Jinzhi Lois1,* 
, Liu Qing2, Quan Jing2, Ye Qing2, Zhang Xi1, Hua Younan1, Li Xiaomin1
1 WinTech Nano-Technology Services Pte. Ltd.,10 Science Park Road, #03-26, The Alpha Science Park II, 117684, Singapore
2 Silead Inc. Co., Ltd (Shanghai), No.560 Pudong New District, Shanghai, 200010, China
* Author to whom correspondence should be addressed.
Journal of Engineering Research and Sciences, Volume 3, Issue 1, Page # 1-5, 2024; DOI: 10.55708/js0301001
Keywords: Land grid array (LGA) package, Deuterium oxide (D2O), Isotope tracing, HAST, moisture penetration
Received: 25 September 2023, Revised: 10 January 2024, Accepted: 10 January 2024, Published Online: 30 January 2024
APA Style
Lois, L. J., Qing, L., Jing, Q., Qing, Y., Xi, Z., Younan, H., & Xiaomin, L. (2024, January). Application of deuterium Oxide (D2O) Isotope Tracing Technique for Land Grid Array Package Failure Analysis. Journal of Engineering Research and Sciences, 3(1), 1–5. https://doi.org/10.55708/js0301001
Chicago/Turabian Style
Lois, Liao Jinzhi, Liu Qing, Quan Jing, Ye Qing, Zhang Xi, Hua Younan, and Li Xiaomin. 2024. “Application of Deuterium Oxide (D2O) Isotope Tracing Technique for Land Grid Array Package Failure Analysis.” Journal of Engineering Research and Sciences 3, no. 1 (January): 1–5. https://doi.org/10.55708/js0301001.
IEEE Style
L. J. Lois et al., “Application of deuterium oxide (D2O) isotope tracing technique for land grid array package failure analysis,” Journal of Engineering Research and Sciences, vol. 3, no. 1, pp. 1–5, Jan. 2024. doi:10.55708/js0301001
A land grid array (LGA) is an integrated circuit design with a grid of contacts connected to other components of a printed circuit board. LGA is used for various high-speed and high-frequency applications due to its small terminal parasitic inductance. However, LGA packages are non-hermetic, as most the components of the LGA, like epoxy molding compounds, substrates, and resins are not airtight. These components can absorb moisture from working environment, and the moisture penetration will give rise to package reliability problems. In this study, a batch of LGA packages encountered electrical malfunction after Highly Accelerated Stress Tests (HAST) 85°C/85%RH reliability test 96 hours. The failure mode was causing the connected display panels showing white dots, as the LGA were used to control the external display panels. Although hot spot testing through thermal imaging was performed, it could not locate the failure point of the die. Traditional non-destructive tests, like X-ray inspection and Scanning Acoustic Microscopy techniques were also performed, but they could not detect any defect of the package which may be contributed to their detection limit. It is suspected that penetration of moisture into the LGA package caused electrical failure, however there is no direct proof to demonstrate this presumption. To solve above challenges, this work employed a new deuterium oxide (D2O) isotope tracing method. Both good and bad LGA packages were loaded in the HAST chamber in which normal water (H2O) was fully replaced with heavy water (D2O). Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was utilized to detected the D signal in the LGA package. By comparison, it was found that the moisture penetration through the via-resin interface of the bad sample was much faster than that of the good sample. Verification test was performed to replace the bad batch substrate (where moisture penetrated fast), and the new samples all passed the HAST test. It is confirmed that it is the via-resin interface in the substrate of the bad samples causing moisture penetration.
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