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In this paper we report three mechanisms causing surface defects on Si sidewalls during Si etching for TSV. The first mechanism causing surface defects was a downward surface-defect formation due to the participation of the residual polymerizing gas in the transition periods between passivation steps and etch steps. The second mechanism was an upward surface-defect formation due to etchant attacking the interface between the Si and the sidewall polymer. Although the sidewall polymer was thick enough to protect the Si surface, it was not possible to avoid surface defects if the etch step was not switched to the following passivation step in time. The third mechanism was a sponge-like surface-defect formation caused by either poor polymer depositions or voids inside the sidewall polymer. The sponge-like surface defects were formed by Si isotropic etching through the weak points of the sidewall polymer. All three surface defects were considered as the major factors on TSV integration and packaging reliability issues.

was found to be dependent on the electroplating current. It was shown that longer transient times were correlated with a greater incorporation of plating impurities for the bath chemistry used in this study. The present work shows that the grain growth that occurs during the resistance transient is initiated by the formation of abnormally large grains, where the transformed structure reveals strong E3 type twinning. The increase in the fraction of twin grain boundaries with transient time is quantified, and a comparison of the time dependencies of resistivity and the grain size shows that the MayadasShatzkes model can qualitatively describe grain boundary resistivity. X-ray analysis revealed that the structure is strongly { 11 1) textured and the contribution of (200) texture increases during transformation. Atomic Force Microscopy (AFM) and imaging with the secondary electron in-lens detector showed that surface morphology of Cu structures varies across the film and is dependent on the plating current.

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