Interface imaging process for high resolution and high aspect ratio patterning

A novel interface imaging process is proposed for high resolution and high aspect ratio patterning. The photoresist system is composed of a top acid-labile silicon-containing polymer, an intermediate layer containing a photoacid generator, and a cross-linked bottom layer. Upon patternwise exposure to UV light, acid is produced in exposed areas of the intermediate layer. The acid diffuses into the top layer during the post-exposure bake and induces cross-linking of the silicon-containing polymer. After development of the top layer, the pattern is transferred into the bottom layer through an oxygen reactive ion etching. High resolution and high aspect ratio patterns were obtained by controlling the penetration depth of acid and the anisotropic reactive ion etching process.