Morphologies of the Selectively Etched SAC305-TiO2 solder with 1812 SMD Capacitor Package
1School of Materials and Mineral Resources Engineering, University Science Malaysia, Nibong Tebal, Penang, Malaysia
2School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang, Malaysia
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Abstract : Morphological comparisons of the etched Sn-3.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu-TiO2 with the 1812 surface mount device capacitor were achieved by the aid of electrochemical etching. The removal of the β-Sn phase were successfully attained at a fixed potential of -350 mV for 120 s. Stable current responses at 0.00223 A were recorded for the Sn-3.0Ag-0.5Cu and 0.00235 A for the Sn-3.0Ag-0.5Cu-TiO2. The phase analysis indicated the selective removal of the β-Sn. The TiO2 reinforcement particles were detected near the Cu6Sn5 intermetallic compound layer in the Sn-3.0Ag-0.5Cu-TiO2. Removal of the surrounding β-Sn allow clear observation on the intermetallic compound size refinement by the TiO2. The package displacement measured for the Sn-3.0Ag-0.5Cu-TiO2 was 78.6 μm. Voids formation were obvious in between the capacitor and the FR4 substrate for the SAC305. The presence of the TiO2 favored higher formation of the Ag3Sn network which improves the joint reliability between the capacitor and the FR4 substrate.
Keywords : SAC305,Morphology,Selective Electrochemical Etching,SMD Capacito