Mask inspection method for 45nm node device

Abstract

Sensitivity of newly developed photo mask inspection tool with reflective optic was evaluated for 45nm DRAM device. To get the required defect sensitivity of mask, printability of mask defect on wafer were simulated using in house simulation tool. Simulation results were compared with inspection results. Characteristic and sensitivity comparison between conventional transmissive and reflective optic tools were evaluated for several types of mask layer of 45nm and 55nm DRAM according to pixel size of detector of inspection tools. This reflective optic with short working distance was equivalent in sensitivity to transmissive optic tool. Mask for 45nm DRAM can be qualified by current status of the art inspection tools.