Development of 1.6 μm Fine- Pitch RDL Damascene Process using Low-NA i-Line Stepper and a New Negative-tone Photosensitive Dielectric Material

Abstract

This paper introduces a new negative-tone photosensitive dielectric material designed for use in fine-pitch RDL (re-distribution layer) damascene processes. Using a 3.6 μm thick photosensitive dielectric material for the metal layer, dense line/space features with a critical dimension (CD) of 1.6 μm was successfully patterned. For the via layer, a 2.5μ m thick photosensitive dielectric material was patterned to achieve a target CD of 2.0μ m, with a centre-to-centre via pitch of 4.0μ m. Both layers demonstrate excellent patterning performance with a wide process window. All exposures were performed using a low NA (0.16) i-line exposure tool, AP300, from Veeco (generation 1).