Formation of a Negative Photoresist Thin Film by Spin Coating

Experimental film formation of a rubber-based negative photoresist by spin coating relative to that of a diazoquinone sensitized positive photoresist was investigated. The baked film produced with the negative photoresist is thinner than that produced with the positive photoresist in the first stage of the spinning in spite of the heavy wet weight due to the low solid content, but becomes thicker in the later stages in spite of the light wet weight due to the high solid content. The thickness deviation of the baked film of the negative photoresist is larger than that of the positive photoresist during the entire spinning process because the negative photoresist always had a high viscosity during the spinning process. The solvent evaporation rate of the negative photoresist is higher than that of the positive photoresist up to the intermediate stages of the spinning due to the higher vapour pressure and activity.