超级化学镀铜填充微道沟的研究

超级化学铜填充技术不仅可以应用于半导体超大集成电路铜互连线, 而且可以应用于三维封装. 研究了不同浓
度、不同分子量的PEG 对以甲醛为还原剂的化学镀铜溶液中铜的沉积速率的影响. 随着添加剂PEG 浓度和分子量的
增大, 化学铜的沉积速率明显降低. 电化学研究结果表明PEG 通过抑制甲醛的氧化反应降低化学铜的沉积速率, PEG
分子量越大, 对化学铜的抑制作用越强. 利用PEG-6000 对化学铜的抑制作用和在溶液中低的扩散系数, 采用添加
PEG-6000 的化学镀铜溶液, 成功地实现了宽度在0.2 μm 以下微道沟的超级化学填充. 就PEG 的分子量、微道沟的深
径比等因素对超级化学铜填充的影响也做了研究.

Bottom-up Filling for Submicro-Trenches by Electroless Copper Plating

Bottom-up filling of electroless copper can be applied not only to semiconductor ultra-
large-scale integration for copper interconnect lines, but also to three-dimensional package. The relationship
of deposition rates of an electroless copper bath with the concentration and molecular weight (Wm)
of polyethylene glycol (PEG) was investigated. The deposition rates decreased with the increases of PEG
concentration and Wm. The result of liner sweep voltammetry measurement showed that PEG inhibited the
electroless copper deposition and the inhibiting effect increased with an increase of PEG (Wm). Bottom-up
filling of trenches was achieved by addition of PEG-6000 in its concentration gradient from the top to the
bottom. The effects of PEG Wm and depth-to-width ratio of the trenches (aspect ratio) on the bottom-up filling
of electroless copper were also studied.