On-track process for patterning hardmask by multiple dark field exposures

A method of forming a microelectronic structure, said method comprising:

• (a) providing a substrate having a surface;
• (b) applying a hardmask composition adjacent the substrate surface, said hardmask composition comprising a polymer dispersed or dissolved in a solvent system, said polymer comprising recurring monomers of
• where:
• each R1 is individually selected from the group consisting of —H, and alkyl groups;
• and
• each R2 is individually selected from the group consisting of —H, and silicon-containing moieties selected from the group consisting of
• where each R3 is selected from the group consisting of alkyl groups, and each R4 is selected from the group consisting of n-butyl, t-butyl, and alkyl groups, and wherein at least one of said R2 is a silicon-containing moiety;
• (c) baking said hardmask composition to yield a hardmask layer;
• (d) applying a photosensitive composition to form a first imaging layer on top of said hardmask layer;
• (e) exposing said first imaging layer to activating radiation to yield exposed portions in said first imaging layer;
• (f) contacting said first imaging layer with a developer so as to remove said exposed portions of said first imaging layer, wherein said contacting also results in the removal of portions of said hardmask layer beneath said exposed portions in said first imaging layer, yielding a patterned hardmask layer;
• (g) contacting said first imaging layer with an organic solvent so as to remove said first imaging layer;
• and
• (h) applying a second photosensitive composition to form a second imaging layer on top of said patterned hardmask layer, without applying additional hardmask composition to said substrate.