Selective ALD Mo Deposition in 10nm Contacts

Selective atomic layer deposition (ALD) of Mo is explored to fill 10nm contacts in a 2 nm node test vehicle. The ALD Mo deposition is highly selective towards the dielectrics (SiO2, low-k OSG3.0, SiCN), and deposits selectively on the bottom Ru routing contact layer. Barrierless Mo via fill levels in the range of 10-20nm are obtained without detecting Mo in the dielectrics of the stack. The resistance of the Mo in MP24 vias with aspect ratio (AR) 2 is ~ 50Ω. Further resistance reduction is expected upon removing the top interfacial oxide introduced by an air break during metallization. The reliability shows that stress induced voiding is not observed for the Mo-Cu metallized system. Additionally, the via electromigration failures are only observed in the connecting Cu top trench, leaving the robust ALD Mo vias intact.