Polyethersulfone-Epoxy Terminated Materials as Thermosetting Resins for Microelectronic Devices

A totally aromatic polyether/sulfone resin (PES-E) was synthesized and tested as an insulating glue in the construction of a Chip-on-Chip (CoC) device. PES-E, essentially constituted of open-chain macromolecules of low molecular mass (m, of about 3000 Da) with hydroxy and/or epoxy end-groups, has a glass transition temperature of about 150 degrees C and is subject to crosslinking at temperatures higher than 320 degrees C. A CoC device was assembled using a five-step process by interposing a layer of PES-E between two chips. After curing, SEM cross section images showed a homogeneous crosslinked resin layer well stuck (flick and shear tests) to both chips. The chemical structure of the chains and the hydroxy/epoxy end-groups ratio were optimized to obtain a crosslinked material with good adhesion and sufficient flexibility to avoid cracking during assembly and use. (C) 2009 Wiley Periodicals, Inc. J Polyrn Sci Part A: Polyrn Chem 47: 5682-5689, 2009