Application of supercritical carbon dioxide electrodeposition for copper filling into nano-holes in heat-treated anodic aluminum oxide template

• Main Authors: De-WeiLin, 林德瑋
• Other Authors: Wen-Ta Tsai
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/9f9arb

碩士 === 國立成功大學 === 材料科學及工程學系 === 105 === Copper metal filling into heat-treated anodized aluminum oxide (AAO) nano-array holes was attempted by electrodeposition involving emulsified supercritical carbon dioxide (sc-CO2) fluid, in comparison with that performed using conventional process at ambient pressure. The AAO template was likely hydrophobic in nature after being heat treated at 860 oC/24h. It had a dimension of about 5 um in thickness with an average hole-size of 60 nm and an aspect ratio of 83. Copper electrodeposition was conducted at 50 oC and at a pressure of 10 Mpa in an electrolyte consisting of 40 vol% of sc-CO2 and 60 vol% of CuSO4 aqueous solution. Both constant potential (-0.4 VPt, -0.5 VPt, -0.6 VPt) and constant current density (-10 mA/cm2) conditions were applied for metal filling. After electrodeposition, the extent of metal filling was examined using a scanning electron microscope (SEM) , and a transmission electron microscope (TEM), both coupled with an energy dispersive spectrometer (EDS). When as-anodized AAO template was used, a higher filling efficiency (in terms of cross section area percentage) was found in sc-CO2 bath than in conventional bath. When heat-treated AAO template was used, copper filling into the high aspect ratio nano-holes could be successfully achieved by sc-CO2 electrodeposition, while it was not possible in conventional bath. The advantage of sc-CO2 electrodeposition over that of conventional process was mainly attributed to the change of hydrophobicity of AAO template induced by heat treatment.