Mask aligner – automated lithography processes
Mask aligners are used in the semiconductor back-end for less critical lithographic processes. In contrast to wafer steppers in the front-end, the photoresist is fully exposed due to the shadowing of the mask structure.
The positioning of the mask over the substrate is carried out using positioning marks, which are applied to the cover during the process using microscopes. In new systems, the accuracy that can be achieved using this method is around ≥ 0.5 µm.
In addition to excellent process stability, mask aligners allow for a very high throughput, making them the first choice for price-sensitive applications, such as microfluidic disposable components.