Semiconductor structure with suppressed STI dishing effect at resistor region

摘要

A method includes forming a first isolation feature of a first width and a second isolation feature of a second width in a substrate, the first width being substantially greater than the second width; forming an implantation mask on the substrate, wherein the implantation mask covers the first isolation feature and exposes the second isolation feature; performing an ion implantation process to the substrate using the implantation mask; and thereafter performing an etching process to the substrate.