Method of simultaneously controlling adi-aei cd differences of openings having different sizes and etching process utilizing the same method

Abstract

A method of simultaneously controlling the ADI-AEI CD differences of openings having different sizes is disclosed. The openings are formed by: forming an ARC and a photoresist layer with a first and a second opening patterns of different sizes therein on a material layer, and etching the ARC and the material layer with the photoresist layer as a mask to form in the material layer a first/second opening corresponding to the first/second opening pattern, wherein the etching recipe makes the first/second opening smaller than the first/second opening pattern by a first/second size difference (ΔS/ΔS) and the difference between ΔSand ΔSis a relative size difference. The method is characterized by that an etching parameter affecting the relative size difference is set at a first value in etching the ARC and at a second value different from the first value in etching the material layer.