Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2008-05-06
2008-05-06
Sarkar, Asok Kumar (Department: 2891)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S633000, C438S906000, C257SE21304
Reexamination Certificate
active
07368383
ABSTRACT:
A method for treating a copper surface of a semiconductor device provides exposing the copper surface to a citric acid solution after the surface is formed using CMP (chemical mechanical polishing) or other methods. The citric acid treatment may take place during a cleaning operation that takes place in a wafer scrubber, or subsequent to such an operation. The citric acid treatment removes copper oxides that form on copper surfaces exposed to the environment and prevents hillock formation during subsequent high temperature operations. The copper surface is then annealed and the annealing followed by an NH3plasma treatment which again removes any copper oxides that may be present. The NH3plasma operation roughens exposed surfaces improving the adhesion of subsequently-formed films such as a dielectric film preferably formed in-situ with the NH3plasma treatment. The subsequently-formed film is formed over an oxide-free, hillock-free copper surface.
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Lee Wen-Long
Lin Shih-Chi
Wang Francis
Wu Sez-An
Duane Morris LLP
Sarkar Asok Kumar
Taiwan Semiconductor Manufacturing Co. Ltd.
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