XT 1700 i Immersion Lithography

Immersion lithography is a form of projection lithography used in semiconductor manufacturing. Projection lithography systems image a reticle pattern onto a light-sensitive wafer through an optical system. Immersion systems interpose a liquid between the final lens element and the wafer during exposure.

Many immersion lithography systems of this class operate as step-and-scan tools. In a step-and-scan tool, the reticle and the wafer move in a synchronized scan during each exposure of a small field. After each field is exposed, the wafer steps to the next field and the exposure scan repeats across the wafer surface.

Lithography tools occupy a central position in wafer fabrication, patterning each layer of a device. Before exposure, the wafer is coated with a light-sensitive resist and aligned to previously formed patterns. After exposure, the resist is developed and the pattern is transferred into underlying films by etching and other process steps.

Immersion lithography systems are used to produce the patterned layers of integrated circuits. The exposed patterns define transistor features, contact holes, and metal interconnect levels. The same class of tooling is also used in other technologies that require high-resolution photopatterning.