Abstract
Standard positive tone chemically amplified resists usually suffer from a latent image instability caused by uncontrolled acid diffusion after their exposure. To improve the delay stability, novel resist additives with both high nucleophilicity and radiation sensitivity have been developed. Typical representatives include opium hydroxides, alkoxides, or carboxylates, which act as strong bases in aqueous media. The compounds decompose into neutral fragments upon exposure but preserve their basic character in the unexposed areas. This enables a selective neutralization of the diffusing acid in areas of intended unexposure. When applied to a chemically amplified resist system the shelf life of the resist solution, the film life stability and the delay time stability are significantly improved, while the photospeed is only marginally deteriorated. Enhanced resolution capability, and improved latitudes are additional benefits.
