US Patent 7670643 Method and system for dispensing resist solution

An apparatus and method for dispensing a solution on a substrate is described in which the solution is dispensed through a solution nozzle assembly while the substrate is rotated. As the solution is dispensed, the solution on the substrate forms a wave front that radially spreads from the substrate center to the substrate edge. The dispensing of the solution is performed in such a way that the solution is dispensed at a radial location substantially equivalent to or less than the radial location of the wave front at any instant in time.