Photoresist

Photoresist is a crucial material in semiconductor manufacturing processes. It is a light-sensitive polymer that can change its solubility or physical properties when exposed to light.

How it Works

When a photoresist is applied to a substrate such as a silicon wafer, it forms a thin film. Exposure to ultraviolet or other specific wavelengths of light causes a chemical reaction in the photoresist. This reaction changes the solubility of the exposed areas. For positive photoresists, the exposed areas become soluble in a developer solution, allowing those regions to be removed. In contrast, negative photoresists become insoluble in the developer where exposed, leaving the unexposed areas to be washed away.

Applications

Photoresists are used for creating patterns on wafers. This is essential for fabricating integrated circuits, microelectromechanical systems (MEMS), and other semiconductor devices. The precise patterning enabled by photoresists allows for the formation of features such as transistors, interconnects, and vias with high precision and resolution.

Types

There are different types of photoresists, including positive and negative ones, as well as those optimized for different wavelengths of light and specific semiconductor manufacturing processes.