EUV resist etch durability improvement and pattern collapse mitigation

A method for patterning a substrate, the method comprising:

• receiving a first patterned layer overlying a material layer to be etched on a substrate, the first patterned layer being composed of a resist material having (i) material properties that provide lithographic resolution of less than about 40 nanometers when exposed to extreme ultraviolet (EUV) radiation lithography, and (ii) material properties that provide a nominal etch resistance to an etch process condition selected to etch the material underlying the first patterned layer, wherein the first patterned layer is characterized by features having a height-to-width ratio of less than 1.5-to-1;
• over-coating the first patterned layer with an image reversal material such that the image reversal material fills and covers the first patterned layer, wherein the image reversal material has material properties that provide an etch resistance to the etch process condition that exceeds the nominal etch resistance;
• removing an upper portion of the image reversal material such that top surfaces of the first patterned layer are exposed;
• removing the first patterned layer such that the image reversal material remains resulting in a second patterned layer;
• and
• controlling one or more selected operating variables which are concurrently controlled during one or more operations including over-coating the first patterned layer with the image reversal material, removing the upper portion of the image reversal material, and/or removing the first patterned layer such that the image reversal material remains results in a second patterned layer, the controlling done in order to achieve patterning objectives.