Notable improvement in porous low-k film properties using electron-beam cure method

High performance Low-k dielectric with porous structure (k=2.2) is realized by Electron-Beam (EB) cure technique, and applied to a 90 nm node Cu/Low-k multilevel damascene process. By EB curing, while maintaining a low k value, both mechanical strength and adhesion strength of lower interface have been improved 1.5 times respectively. This strengthening effect was actually confirmed as avoiding peeling by CMP process. In addition, introduction of EB cure technique reduced spin on dielectric (SOD) cure temperature and time, therefore the thermal budget was reduced drastically. It was also considered that this EB cure technology will be very effective in future 65 nm node devices.