A method for coating low viscosity materials onto a wafer to form a uniform film.
After a wafer is rotated at a first rotation speed, coating solution is dispensed
onto the wafer. The wafer is decelerated to a second rotation speed at a first
deceleration rate to spread the coating solution. Next, the wafer is slowly decelerated
to a third rotation speed at a second deceleration rate considerably lower than
the first deceleration rate, so the coating solution reflows to the center of the
wafer. The wafer is then quickly accelerated to a fourth rotation speed at a third
acceleration rate larger than the first deceleration rate to spread the coating
solution again.
