The process begins with the application of a photoresist layer onto a substrate, such as a silicon wafer. This layer is then exposed to a specific pattern of light, typically using photomasks. The exposed areas of the photoresist undergo a chemical change. In the case of positive photoresists, the exposed regions become more soluble and can be washed away, leaving behind a patterned resist. For negative photoresists, the unexposed areas are removed, resulting in a similar patterned effect.
