Investigation of PEG adsorption on copper in Cu2+-free solution by SERS and AFM
Investigation of PEG adsorption on copper in Cu2+-free solution by SERS and AFM
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SERS 和 AFM 研究 PEG 对无 Cu2+ 溶液中铜的吸附
DOI：
10.1016/j.electacta.2012.06.039
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发表时间：
2012-09-01
影响因子：
6.6
通讯作者：
Wen, Lei
中科院分区：
文献类型：
--
作者：
Jin, Ying;Sun, Ming;Wen, Lei
采用原位表面增强拉曼光谱（Sers）和原子力显微镜（AFM）研究了聚乙二醇（PEG）在酸性无Cu 2+电解液中的表面吸附行为。Sers和AFM研究表明，在所有考察的电位下，PEG的吸附量在接近30 min的浸泡时间内逐渐增加，然后达到稳定状态。结果表明，在所研究的范围内（-0.15 V至-0.35 V（SCE）），在相对负的电位，更多的PEG吸附在表面上，并形成较不紧凑的集群桩。原位AFM图像显示，在含有PEG、Cl-和大量H2SO 4的电镀液中，吸附的PEG呈扁锥形团簇，团簇底部直径为几十纳米，高度为几纳米。吸附团簇的直径随时间和阴极极化的增加而增大，而吸附团簇的高度增加不明显。目前的研究结果表明，PEG主要有助于在纳米尺寸的通孔和沟槽的外表面的沉积速率缓慢，吸附的PEG簇的尺寸太大，移动到微小的结构。(C)2012爱思唯尔有限公司保留所有权利。
The surface adsorption behavior of polyethyleneglycols (PEG), a wide-used additive in damascene copper plating, was investigated in acidic Cu2+-free electrolyte in the presence of PEG and Cl- by in situ surface enhanced Raman spectroscopy (SERS) and atomic force microscopy (AFM) under potentiostatic conditions. Both SERS and AFM studies indicate that the adsorption amount of PEG gradually increases within similar to 30 min immersion time at all the examined potentials prior to reaching steady status. It is demonstrated that, at relatively negative potentials in the examined range (-0.15 V to -0.35 V(SCE)), more PEG are adsorbed on the surface and form less-compact clusters in piles. In situ AFM images show that, in the damascene plating electrolyte containing PEG, Cl- and large amount of H2SO4, the adsorbed PEG appear to be flat-cone shaped clusters with a bottom diameter of several tens of nanometers, and a height of several nanometers. The diameters of the adsorbed clusters increase with time and the cathodic polarization, while the heights of the adsorbed clusters do not increase obviously. The present results suggest that PEG mainly contribute to the slow deposition rate at the external surface of nanometer-sized vias and trenches, for the dimensions of adsorbed PEG clusters are too big to move into the tiny structures. (C) 2012 Elsevier Ltd. All rights reserved.