Organic levelers have been essential additives for Cu electrodeposition to achieve defect-free filling of through-silicon vias (TSVs). They selectively inhibit Cu deposition on top of TSVs, avoiding the occlusion of TSV openings and concentrating Cu deposition inside the TSVs. We recently reported that iodide ions (I⁻) can act as an inorganic leveler to induce defect-free TSV filling. However, it was found that I⁻ considerably decreased the efficiency of Cu electrodeposition because of the formation of an unstable CuI suppression layer on top of the wafer. The CuI layer easily detached from the wafer, and additional electrons were consumed to reestablish the suppression layer during gap-filling. This study introduces a TSV filling process with bromide ions (Br⁻) as an alternative to I⁻. Although the suppression strength of Br⁻ to Cu electrodeposition is weaker than that of I⁻, Br⁻ forms a more stable suppression layer that does not reduce the efficiency of Cu electrodeposition, enabling high-speed TSVs filling. As a result, the filling rate with Br⁻ was twice as fast as that with I⁻ at the same applied current density; thereby TSVs 60 μm deep and 5 μm in diameter were completely filled in 500 s.

中文翻译：

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溴离子作为高速TSV填充的整平剂

有机整平剂一直是用于铜电沉积以实现无缺陷填充硅通孔（TSV）的重要添加剂。它们选择性地抑制TSV顶部的Cu沉积，避免了TSV开口的堵塞，并使Cu沉积在TSV内部。我们最近报道，碘离子（I ^- ）可以作为无机矫直机以诱导无缺陷的TSV填充作用。然而，人们发现，我^-显着降低，因为不稳定的CuI抑制层在晶片的顶部形成的铜电沉积的效率。CuI层很容易从晶片上脱落，并且在间隙填充过程中消耗了额外的电子以重新建立抑制层。本研究中引入了一个TSV填充过程与溴离子（BR ^-）作为I ⁻的替代。虽然BR的抑制强度^-对铜的电沉积是比的我弱^- ，溴^-形式更稳定的抑制层，其不降低铜电沉积的效率，实现高速的TSV填充。其结果是，与溴填充率^-是快两倍，与我^-在相同的施加的电流密度; 从而在500 s内完全充满了深60μm，直径5μm的TSV。