Patent ID: 11862465
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 18:
19. A pattern formation method, comprising:
forming an underlying layer over a substrate;
forming a multilayer resist system over the underlying layer, the multilayer resist system including a bottom layer, a middle layer and a photo resist layer;
forming a photo resist pattern in the photo resist layer by a lithography operation;
etching the middle layer by using the photo resist pattern as an etching mask;
removing the photo resist pattern;
etching the bottom layer by using the patterned middle layer as an etching mask;
performing a softening process to the patterned middle layer; and
after the softening process, removing the patterned middle layer,
wherein the softening process includes an ion implantation process comprising providing ions towards the patterned middle layer at an angle of 0° to 20° relative to an upper surface of the substrate so that the ions applied to the middle layer are applied only to a top surface of the middle layer.