Photoresist compositions and method for multiple exposures with multiple layer resist systems

A method comprising:

• forming a first film of a first photoresist on a substrate, said first photoresist comprising a first polymer, a thermal base generator capable of releasing a base above a first temperature, a first photosensitive acid generator capable of generating an acid upon exposure to radiation, and a first solvent, said first photoresist having the properties of being substantially soluble in said solvent and becoming substantially insoluble in said solvent after heating said first photoresist to above a second temperature;
• patternwise imaging said first film through a first mask, said imaging comprising exposing at least one region of said first film to radiation, resulting in producing a first acid catalyst in said at least one exposed region of said first film;
• after said imaging, developing said first film in an aqueous base, resulting in removing base-soluble exposed regions of said first film and forming a first patterned layer of said first film;
• and
• baking said first patterned layer above said first temperature and above said second temperature, wherein resulting from said baking said first thermal base generator releases a base within said first patterned layer, wherein resulting from said baking said first patterned layer becomes substantially insoluble in said first solvent.

A resist composition, comprising:

• a polymer which is substantially soluble in a first solvent and which becomes substantially insoluble in said first solvent after heating said polymer to a first temperature of about 140° C. or greater;
• a thermal base generator selected from the group consisting of (i) structure:
• wherein each R1 or R2 is independently selected from the group consisting of a hydrogen atom, a linear alkyl, a branched alkyl, a cycloalkyl, a halogenated linear alkyl, a halogenated branched alkyl, a halogenated cycloalkyl, an aryl, a halogenated aryl, and combinations thereof, and (ii) dimers of said structure (i);
• and
• a photosensitive acid generator capable of releasing acid upon exposure to radiation.