Dunbar P. Birnie, III and M. Manley
Source: Physics of Fluids, 9, (1997) pp 870-875
Abstract: Fluid flow and fluid evaporation both contribute to
the overall rate of thinning during spinning of a fluid on a disk. Laser
interferometry of solvent thinning behavior on spinning silicon wafers
was performed to yield plots of solvent thickness evolution. These plots
of thickness versus time were then analyzed to understand the respective
contributions of viscous flow and evaporation to the thinning. A technique
is described for extracting both the viscosity and the evaporation rate
from the interference data. Well understood solvent systems are examined
as test cases for this deconvolution. It is also demonstrated that nonevaporating
fluids can be analyzed, even though their thickness evolution has no easily
referenced endpoint to the thinning, in contrast to the volatile solvents
which are rapidly spun dry.