Patent ID: 6147010
Filing Date: 2000-11-14
Classification: G03F,H01L

Abstract:
A method of coating a wafer, comprising:selecting a slow-drying solvent, wherein selecting a slow drying solvent includes selecting a solvent having a low vapor pressure, wherein the vapor pressure of the solvent is equal to or is lower than the vapor pressure of diacetone alcohol; wherein said solvent comprises diacetone alcohol;dispensing less than 1.0 cc of the solvent on the wafer as a pre-wet step, wherein the less than 1.0 cc of the solvent has an evaporation rate of greater than 1 second;spinning the wafer until the solvent is distributed across the wafer surface wherein the low vapor pressure solvent serves as the means for controlling wetting on the wafer surface;dispensing a photoresist solution on the wafer having solvent on its surface;spinning the wafer until the photoresist is distributed across the wafer surface wherein controlling the wetting on the wafer surface with the low vapor pressure solvent allows for even distribution and wetting of the wafer surface using less solvent than conventional acetate solvents and reduces the surface tension such that the low vapor pressure solvent reduces the amount of photoresist necessary to coat the entire wafer; andwherein the longer dry time associated with the low vapor pressure solvent allows the solvent more time to flow and evenly distribute across the wafer surface than possible with conventional acetate solvents which reduces a ramping rate for spinning the wafer as required to flow and evenly distribute a solvent across the wafer surface wherein said conventional acetate solvents are those having higher vapor pressures than diacetone alcohol.