title: Study of a two-stage photobase generator for photolithography in microelectronics.
abstract: The investigation of the photochemistry of a two-stage photobase generator (PBG) is described. Absorption of a photon by a latent PBG (1) (first step) produces a PBG (2). Irradiation of 2 in the presence of water produces a base (second step). This two-photon sequence (1 + hν → 2 + hν → base) is an important component in the design of photoresists for pitch division technology, a method that doubles the resolution of projection photolithography for the production of microelectronic chips. In the present system, the excitation of 1 results in a Norrish type II intramolecular hydrogen abstraction to generate a 1,4-biradiacal that undergoes cleavage to form 2 and acetophenone (Φ ∼ 0.04). In the second step, excitation of 2 causes cleavage of the oxime ester (Φ = 0.56) followed by base generation after reaction with water.
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, United States. njt3@columbia.edu
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Turro
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Li
authors.forename: Steffen
authors.initials: S
authors.lastname: Jockusch
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hagiwara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Okazaki
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Mesch
authors.forename: David I
authors.initials: DI
authors.lastname: Schuster
authors.forename: C Grant
authors.initials: CG
authors.lastname: Willson