Metal filling of micro-trench patterns by Ni electrodeposition at different potentials, inhibitor concentrations and angles to paddle agitation
Chou, Samuel Han Jian
Date of Issue2016
School of Mechanical and Aerospace Engineering
Microscale parts are manufactured using mechanical machining or manual labour. However, the products are not precise and the process is time consuming. Hence, electroplating is introduced. This report is to investigate the optimal conditions for electroplating to produce voidless metal filling at the shortest amount of time. Hot embossing machine is used to fabricate patterned polymer. The patterns are trenches placed at different angles. Then it was coated with gold by sputtering and was placed into nickel electroplating bath with Polyethylene Glycol (PEG) added. The electroplated sample was embedded in acrylic resin, then cut and polished. Thickness of deposit in trench was measured. Results have shown that there is no strong correlation between angles of trenches placed and deposition rate. In addition, increasing potentials and concentration of PEG lead to an increase in the deposition rate in the trench. As larger current caused more nickel to break down into ions, larger effects of the inhibitor fill up the trench in a shorter period of time. In conclusion, to have voidless metal filling for 6 hrs of electroplating, 20 ppm of PEG is added with potential of -0.95 V. However, more experiments need to be done to investigate wider range of conditions to further decrease the amount of time for electroplating process.
Final Year Project (FYP)
Nanyang Technological University