This paper presents preliminary data on 300 nm wafer coatings by comparing photoresist coats on 150 nm, 200 mm and 300 mm wafers. Conventional methods of applying photoresist have ben prove effective on wafers with diameters up to 200 nm. How well 150 mm and 200 mm coating processes apply to 300 mm substrates is the focus of this paper. Spin speed versus photoresists thickness curves will be reviewed for all three wafer sizes.Additionally, two major coating uniformity factors, photoresist and cool plate temperature, will be studied for 200 mm and 300 mm wafers.