Patent ID: 9156306
Filing Date: 2015-10-13
Classification: B44C,B82Y,G03F,H01L

Abstract:
1. A lithographic method for etching a pattern with high density based on a combination of several less dense partial patterns, the method comprising: forming a sacrificial layer on a substrate; etching the sacrificial layer according to a first partial pattern comprising parallel lines; forming spacers on edges of portions of the sacrificial layer thus etched; removing the sacrificial layer to leave only the spacers, said spacers defining a second partial pattern of at least four parallel lines comprising two adjacent central lines and two outside lines; depositing a complementary layer of a material different from that of the spacers between the spacers, the complementary layer having a thickness less than or equal to the height of the spacers; locally etching the complementary layer according to a third partial pattern so as to define on the substrate a final pattern resulting from the combination of the second and third partial patterns, said third partial pattern comprising at least one region which extends in a direction perpendicular to said two adjacent central lines of spacers, between the two adjacent central lines, and which has two end sides located on said two adjacent central lines of spacers without going in this direction beyond the adjacent central lines; and performing a thermal treatment, after said local etching, capable of making profiles of the complementary layer flow along the spacers.