FORMATION OF A POSITIVE PHOTORESIST THIN-FILM BY SPIN-COATING - INFLUENCE OF ATMOSPHERIC-TEMPERATURE

Experimental formation of a positive photoresist film by spin coating at various atmospheric temperatures was investigated. The weight of th e photoresist solution on a wafer during spinning decreases sharply du ring the first stage of spinning and gradually during the later stages . At a high temperature, the rate of outflow increases and that of sol vent evaporation decreases in the initial stage of spinning, but the f ormer decreases and the latter increases in the intermediate stages. I n the later stages, both of them decrease. The baked film spun at a hi gh temperature is thin up to the intermediate stages of spinning due t o the higher rates of outflow in the initial stage and evaporation in the intermediate stages more than that at a low one. However, it becom es thick in the later stages due to the lower rates of outflow and eva poration.