Effect of pH on tungsten removal from chemical mechanical polishing (cmp) slurry using dowex marathon c resin of ion exchang
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Date
2018-06
Authors
Nur Husni Ahmad
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Abstract
The chemical mechanical polishing slurry is widely used in the semiconductor
industry as a polishing agent to polish the surface of wafer. The polishing process involve
the chemical and mechanical action to remove the modified layer on the surface of the
wafer by tungsten slurry. The recovery of the tungsten slurry is important to help reducing
the cost of operation and reduce the production of wastewater by the industry. The recovery
of spent tungsten slurry is study by using the ion exchange process by using the cation
resin. Cation resin used is classified as strong acid cation exchange which is the Dowex
Marathon C resin. The parameter that consider in this study is the pH different of the spent
tungsten slurry. The study on the characterization of the tungsten slurry is vital to
understand the best recovery method for the tungsten slurry. The study of characterization
of tungsten slurry involve the pH, metal content, conductivity, zeta potential and mean
particle size where the change in pH of slurry will affected the conductivity, zeta potential
and mean particle size of the slurry. The pH used in this study is 3.84, 5.26, 8.50 and 10.84
with amount of resin used is 5g, volume of spent slurry is 150 mL and time contact between
resin and slurry is 120 minutes. As a conclusion, the removal of tungsten showed that the
best removal in the acidic pH with 9.70% removal at pH 3.84 and the iron removal from
slurry showed that the best removal is when the pH is alkali with 39.49% at pH 10.84.