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

Abstract

Single damascene (SD) Cu/Aurora ® 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 ® 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.

Integration of Porogen-Based Low-k Films: Influence of Capping Layer Thickness and Long Thermal Anneals on Low-k Damage and Reliability

“…A metal hard mask (MHM) approach is chosen to limit the exposure of the low-k material to the ashing plasma. 1) A schematic cross-section of the stack prior to etching of the MHM is shown in Fig. 1.…”