PROJECT TITLE :

Improvement of Rough Interface Between Barrier/Seed Layer and Porous Ultralow k Film for 28nm Technological Node and Beyond

ABSTRACT:

With crucial dimension of device scaled down to twenty-eight nm technological node and beyond, porous ultralow k (PULK) film as an insulator is employed in Cu interconnects to additional cut back resistance-capacitance (RC) delay. The combination of the PULK film faces a lot of severe challenges due to the presence of porosity. Plasma treatments and wet cleaning processes are thought-about to be important steps to impact the PULK film properties. During this paper, the effects of the various plasma treatments and wet cleaning processes on the PULK films were investigated. Results indicated that NH3, N2, and CHF3 plasma treatments resulted in the formation of a thin and densified layer on the surface of the PULK films, which prevented TaN/Ta barrier diffusing inside the pores to avoid forming rough interface. Further, specific EKC520 product + dilute hydrofluoric acid (DHF) were used to scrub the PULK film treated by the CHF3 plasma, and the rough interface was observed when the barrier deposition. Moreover, the precise EKC520 product was used to wash the PULK film treated by the N2 plasma, and there was sleek interface when the barrier deposition. But, the DHF chemical may remove the skinny and densified layer from the surface of the PULK film to cause the re-exposure of pores. During barrier deposition, the TaN barrier subtle inside pores ensuing in the formation of the rough interface.