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Vol.40, No.9, 995 ~ 1001, 2002
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| Title |
| Electronic , Magnetic & Optical Materials : Evaluation of Thermal Deformations in Flip - Chip Package Using Electronic Speckle Pattern Interferometry |
| 장우순Woo Soon Jang,이백우Baik Woo Lee,김동원Dong Won Kim,정증현Jeung Hyun Jeong,백경욱Kyung Wook Paik,권동일Dong Il Kwon,나전웅Jae Woong Nah |
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| Abstract |
| In this study, electronic speckle pattern interferometry (ESPI) was applied to a non-destructive and real-time evaluation of the thermal deformation in a flip-chip package. The displacement resolution of ESPI was improved with magnifying lenses, and ESPI was modified to measure the deformation of micro systems. The flip-chip package thermally deforms with increasing temperature, and the difference in the thermal expansion between the chip and the PCB induces the micro-failure at the solder joint. To evaluate the level of thermal deformation precisely, the horizontal and vertical deformations were measured in the temperature range of 25℃ to 125℃ in situ using the resolution-enhanced ESPI to a sub-micrometer scale. From the experimental results, it was found that the CTE (coefficient of thermal expansion) difference between the chip and the PCB leads to shear strain at the solder joint. In addition, the shear strain could be evaluated at each solder joint. To verify these experimental results, the finite element analysis(FEA) results were compared with the ESPI results. The FEA results were similar to the ESPI results, which confirmed the adequacy of our application. |
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