Polymers, methods of use thereof, and methods of decomposition thereof

A method for fabricating a structure, comprising:

• disposing a photodefinable polymer onto a surface, wherein the photodefinable polymer includes a sacrificial polymer and a photoinitiator selected from a negative tone photoinitiator and a positive tone photoinitiator;
• providing a gray scale photomask, wherein the gray scale photomask encodes optical density profiles defining three-dimensional structures having areas with non-rectangular cross-sections;
• exposing the photodefinable polymer through the gray scale photomask to optical energy;
• and
• removing portions of the photodefinable polymer to form the three-dimensional structures having areas with non-rectangular cross-sections;
• disposing an overcoat layer onto the three-dimensional structures having areas with non-rectangular cross-sections;
• and
• decomposing the photodefinable polymer, thermally, to form three-dimensional air-regions having non-rectangular cross-sections.