Patent ID: 6025012
Filing Date: 2000-02-15
Classification: B05C,B05D

Abstract:
A method for determining film thickness control conditions for use in forming a film of a predetermined thickness on a substrate, wherein the substrate is rotated and a process liquid is discharged towards the rotating substrate from nozzles moving in a radial direction from a center of the substrate, wherein the film thickness control conditions comprise a number of revolutions of the rotating substrate, a rotation duration time of the rotating substrate, a moving speed of the nozzles, a discharge flow velocity of the nozzles, and a temperature of the process liquid, said method comprising:an information receiving step for receiving data of a desired film thickness and a viscosity of the process liquid;a simulation step for, using the data of the desired film thickness and the viscosity of the process liquid received in said information receiving step, simulating a variation of at least one of the film thickness control conditions for each of predetermined unitary positions on the substrate each defined by an area of a ring which encircles the center of the substrate, simulating a behavior of the process liquid on the substrate, and calculating a film thickness for each of the predetermined unitary positions;a control condition determining step for determining the film thickness control conditions based on the at least one of the film thickness control conditions which were varied in said simulation step and based on the film thicknesses calculated in said simulation step;a detecting step for detecting an actual temperature of the process liquid prior to discharging the process liquid onto the substrate;a changing step for changing the film thickness control conditions such that, when the detected actual temperature of the process liquid does not yield a viscosity equal to the viscosity received in said information receiving step, either the discharge flow velocity of the nozzles or the moving speed of the nozzles is changed in accordance with the detected actual temperature of the process liquid, and at least one of a rotation duration time of the substrate and the number of revolutions of the substrate is changed in accordance with the detected actual temperature of the process liquid; anda film forming step for forming a film of the predetermined thickness on the substrate by rotating the substrate, discharging the process liquid onto the rotating substrate from nozzles, and moving the nozzles in a radial direction from a center of the substrate according to the film thickness control conditions;wherein either the rotation duration time of the substrate or the moving speed of the nozzles is set to decrease as the nozzles move from the center of the substrate to a periphery of the substrate.