Low-k properties and integration processes enabling reliable interconnect scaling to the 32 nm technology node

Single damascene (SD) Cu/Aurora reg ULK interconnects with a minimum spacing of 50nm are achieved by using a metal hard mask (MHM) integration scheme, which enables to perform the resist ash before dielectric etch. This patterning scheme is used in combination with a low damage etch technique based on sidewall protection. Interconnect performance and reliability can be further improved by using Aurora reg ULK high modulus (HM), a low-k film with a reduced diffusivity as compared to Aurora ULK, and a comparable k-value of 2.7. The MHM approach results in a limited increase in integrated k-value by 0.1 for ULK HM vs. 0.3 for Aurora reg ULK. The median time dependent dielectric breakdown (TDDB) lifetime is well above the 10 years criterion for spacings down to the 50nm. Finally, the MHM integration scheme enabled fabrication of dual damascene interconnects with Aurora reg ULK HM