Method of forming alignment marks for photolithographic processing

摘要

An alignment method for photolithography, especially for forming an alignment marker on a substrate after ion implantation. A substrate that includes a device region and an alignment mark region is provided. A first patterned photoresist layer is formed over the substrate. The first patterned photoresist layer includes an alignment marker within the alignment mark region and an ion implantation pattern within the device region. Using the first patterned photoresist layer as a mask, an ion implantation is carried out to form a plurality of doped regions. A second patterned photoresist layer that exposes the alignment marker is formed over the ion-implant pattern of the first patterned photoresist layer. Using the alignment marker as a mask, the substrate is etched to form a plurality of recess regions.