Method to reduce metal silicide void formation
A method of forming a low resistance metal silicide layer on a narrow width, conductive gate structure, has been developed. After formation of a metal silicide layer on a conductive gate structure via a self-aligned metal silicide (salicide), procedure, unreacted metal is removed via a selective wet etch procedure. Components of the wet etch procedure incorporated in the metal silicide layer, are next removed via a medium temperature&#8212;high vacuum anneal procedure. Removal of the wet etch components incorporated in the metal suicide layer allow a final anneal procedure to convert the metal silicide layer to a lower resistance metal silicide layer, without voids or agglomerated regions of metal silicide which may have formed during the final anneal if the incorporated wet etch components had not been removed.
Taiwan Semiconductor Manufacturing Company
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Winston Maureen Chi-Wei
Shue Wang Chang