Transcript 下載/瀏覽
版權所有 翻印必究 指導老師 : 林克默 博士 黃文勇 博士 學 生 : 郭怡彣 日 期 : 2011. 03.01 2016/7/13 STUT 太陽能材料與模組實驗室 1 版權所有 翻印必究 Outline 1. 2. 3. 4. Introduction Experiment Results and analysis Conclusion 2016/7/13 STUT 太陽能材料與模組實驗室 2 版權所有 翻印必究 1.Introduction • This study employs an innovative combination of optical tools to examine the microstructure and strain distribution in the Pb-free SnAgCu (SAC) solder interconnects. • Brightfield (BF) and cross-polarizer (XP) imaging techniques of optical microscopy have been used to discern the different grains in the cross-sections. • Digital image correlation (DIC) has been used to quantify deformation and strain, resulting from a thermal loading, on the solder interconnects. 2016/7/13 STUT 太陽能材料與模組實驗室 3 版權所有 翻印必究 2.Experiment • A flip-chip plastic ball grid array (PBGA) package in a 20 * 20 ball grid array (BGA) (CASTIN alloy: Sn–2.5Ag–0.8Cu–0.5Sb) and a flip-chip ceramic ball grid array(CBGA) package in a 25 * 25 BGA (Sn–3.8Ag–0.7Cu) of lead-free board-level interconnects in 1.27 mm pitch were sectioned to produce strips with four rows of solder interconnects. 2016/7/13 STUT 太陽能材料與模組實驗室 4 版權所有 翻印必究 • The assembly with foil heaters was placed on the optical microscope before the heaters were turned on. • BF digital images of the interconnects were captured at room temperature in various magnifications as the reference images for DIC. 2016/7/13 STUT 太陽能材料與模組實驗室 5 版權所有 翻印必究 2016/7/13 STUT 太陽能材料與模組實驗室 6 版權所有 翻印必究 3.Results and analysis 2016/7/13 STUT 太陽能材料與模組實驗室 7 版權所有 翻印必究 2016/7/13 STUT 太陽能材料與模組實驗室 8 版權所有 翻印必究 2016/7/13 STUT 太陽能材料與模組實驗室 9 版權所有 翻印必究 2016/7/13 STUT 太陽能材料與模組實驗室 10 版權所有 翻印必究 2016/7/13 STUT 太陽能材料與模組實驗室 11 版權所有 翻印必究 4.Conclusion • This anisotropic and nonhomogeneous distribution of deformation resulted in plastic deformation along the grain boundaries and near the primary intermetallic precipitates during thermal cycling. • This explains a mechanism of crack initiation and propagation along the grain boundaries and larger primary intermetallics after several thermal cycles. 2016/7/13 STUT 太陽能材料與模組實驗室 12 版權所有 翻印必究 • This would ultimately contribute towards developing optimized process conditions to form different grain structures and intermetallic sizes, and improve the fatigue life of such joints. • A further extension of this technique combined with threedimensional numerical modeling considering the anisotropy would provide a better understanding of the failure mechanism and help to build more accurate reliability models of lead-free solders. 2016/7/13 STUT 太陽能材料與模組實驗室 13 版權所有 翻印必究 Thank you for your attention 2016/7/13 STUT 太陽能材料與模組實驗室 14