Amine gradient process for DUV lithography

Poly(acrylic acid-co-methyl acrylate) was synthesized as a base resin for over-coating materials. By adding l-proline as an amine source to the over-coating material, amine gradient could be useful for lithography. Using this amine gradient process, vertical pattern of 140 nm line/space could be obtained even though the light transmission of photoresist to 193 nm wavelength was not good enough. The amine gradient process might be one of solutions for light absorption problem of photoresist for the next generation lithography.