DUAL ALIGNMENT STRATEGY FOR OPTIMIZING CONTACT LAYER ALIGNMENT

摘要

An improved method for optimizing layer registration during lithography in the fabrication of a semiconductor device is disclosed. In one example, the method comprises optimizing contact layer registration of an SRAM device having a plurality of transistors having active and gate region features extending generally along a channel length (X) direction and a channel width (Y) direction, respectively. The method comprises aligning a contact layer to a gate layer in the channel length direction (X), using gate layer overlay marks to control the alignment of the contact layer in the channel length direction (X) of the semiconductor device. The method further includes aligning the contact layer to an active layer in the channel width direction (Y), using active layer overlay marks to control the alignment of the contact layer in the channel width direction (Y) of the semiconductor device.