Photoresist Coating

 

An amount of photoresist compound is applied onto the surface of the wafer. In semiconductor fabrication, positive resist is often used. The wafer is spun in high speed to evenly spread the coating throughout the surface; ensuring uniformity.

 

The track system or a photoresist processing system is used to execute this task. The spin coating typically runs at 20 to 80 Hz in for 30 to 60 seconds, and produces a layer between 2.5 and 0.5 micrometres thick. The track system continues to develop and bake the wafer, which permits increased adhesion for photoresist. Commonly used photoresist liquids include Ethyl lactate, a colorless liquid, and ethyl pyruvate, which is slightly yellowish. Silicon dioxide is eventually formed.