So am depositing ALD for PERC cell and as an ARC and whenever I do the deposition there is some Al2O3 creeping on the other side of the wafer and cleaning process becomes difficult.Is there anyway to avoid this when depositing Al2O3 by ALD
You could use a polymer photoresist which would be easy to remove after the deposition of Al2O3, i.e. dipping your sample in acetone would dissolve the photoresist film and lift-off the undesired Al2O3 layer from the other side of the wafer.