Title :
Selective isotropic wet etching of TiN and TaN for high k metal gate structure
Author :
Bhattacharyya, Dhiman ; Kuchibhatla, Sridhar ; Sehgal, Akshey ; Yan Ping Shen ; Haiting Wang ; Prasad, Jagdish
Author_Institution :
GLOBALF OUNDRIES, Malta, NY, USA
Abstract :
As the size of the semiconductor device continues to shrink, two integration approaches are used for gate module; (1) gate first, and (2) gate last. The gate last approach requires removal of thin (10-30Å) titanium nitride (TiN) diffusion blocking layers during the “replacement” process after the poly-Si layer is removed. An etch rate study was conducted to evaluate the selectivity of a combined aqueous/solvent cleaning chemistry at various temperatures on blanket TiN and TaN wafers to identify the optimum operating regime. A significant improvement of yield with the application of the new cleaning approach has been observed.
Keywords :
diffusion; etching; high-k dielectric thin films; surface cleaning; tantalum compounds; titanium compounds; TaN; TiN; aqueous/solvent cleaning chemistry; diffusion blocking layers; etch rate study; gate first; gate last; gate module; high k metal gate structure; replacement process; selective isotropic wet etching; semiconductor device; Chemistry; Logic gates; Tin; HKMG; TaN; TiN; selectivity; wet etching;
Conference_Titel :
Advanced Semiconductor Manufacturing Conference (ASMC), 2015 26th Annual SEMI
Conference_Location :
Saratoga Springs, NY
DOI :
10.1109/ASMC.2015.7164500