Successful dual damascene integration of extreme low k materials (k < 2.0) using a novel gap fill based integration scheme

In this communication, a novel scheme known as the etch back/gapfill (EBGF) integration scheme was introduced and shown to overcome most of the well known challenges (2) that are expected to complicate the integration of porous low k materials. It was shown that this integration scheme can be used to successfully generate multi-level dual damascene structures using intermetal dielectric (IMD) materials with k less than 2.0 with promising yield and reliability. It has been demonstrated that EBGF integration is a promising method to integrate fragile porous low k materials into BEOL structures by avoiding most of the major processing issues associated with such materials. By using this scheme, new ultra-low k and extreme low k materials can be introduced with limited modification to the existing dense IMD fabrication infrastructure while increasing the performance of the interconnects substantially. As such the method offers a potential to break through what is now commonly referred to as the "red brick wall" in the BEOL part of the ITRS roadmap.