Imec Demonstrates Pore-sealing Low-k Dielectrics in Advanced Interconnects

Imec announced at SEMICON West that it has demonstrated concept and feasibility for pore-sealing low-k dielectrics in advanced interconnects. The method, based on the self-assembly of an organic monolayer, paves the way to scaling interconnects beyond N5.
 
Imec has developed a method to seal the pores of the low-k material with a monomolecular organic film. The method not only prevents diffusion of moisture and metal precursors into the low-k material, it also might provide an effective barrier to confine copper within the copper wires and prevent copper diffusion into the low-k material.
 
Self-assembled monolayers (SAMs) derived from silane precursors, are deposited from vapor phase on 300mm wafers into low-k during chemical vapor or atomic layer deposition and subsequent Cu metallization. The dielectric constant (k) of the resulting sealing layer is 3.5 and a thickness lower than 1.5nm was achieved. This is key to limit the RC delay increase enabling beyond 5nm technology nodes. As a result, a ca. 30% capacitance reduction was observed after SAM pore-sealing was applied. Moreover, a clear positive impact on the low-k breakdown voltage is observed upon sealing.
 
Imec’s research into advanced interconnects includes key partners as GLOBALFOUNDRIES, INTEL, Micron, Panasonic, Samsung, SK Hynix, Sony, and TSMC.