Patent ID: 10573529

Abstract:
A method for etching a dielectric layer covering at least one top and at least one flank of a semi-conductive material-based structure is provided, including a plurality of sequences, each including successive steps of: a first etching of the layer by plasma using a chemistry including at least a first fluorine-based compound and a second compound chosen from SiwCl(2w+2) and SiwF(2w+2), w, x, y, and z being whole numbers, and oxygen, the first etching: interrupting before complete consumption of the dielectric layer thickness on the flank and after complete consumption of the thickness on the top, and forming a first protective layer on the top and a second protective layer on the flank; and a second etching fully removing the second layer while conserving a portion of the first layer thickness, each sequence being repeated until complete removal of the dielectric layer on the flank.