Metal Etch Stop Under Interconnect Metallurgy
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
By applying a thin layer of an appropriate metal, e.g., cobalt (Co), just prior to the deposition of interconnection metal, e.g., aluminum- copper (Al-Cu), reactive ion etching (RIE) stops after complete removal of the Al-Cu when forming interconnection lines. Selective wet etch removal of the exposed thin Co is achieved with a dilute solution of nitric acid (HNO3). Thus, damage to contacts is avoided since there is never direct exposure of materials under the metallurgy to the RIE process.