| abstract |
Wherein the exposed copper zone on the semiconductor substrate comprises at least one complexing agent selected from the group consisting of (i) bidentate, tridentate, and quaternary complexing agents at a pH between about 5 and 12; And (ii) a wet etch solution comprising an oxidizing agent. In many embodiments, this etch is substantially isotropic and occurs without forming an insoluble species visibly on the copper surface. Such etching is useful in a number of processes in semiconductor fabrication (e.g., partial or complete removal of excess copper portions, planarization of copper surfaces, and formation of recesses in copper-filled damascene features). Examples of suitable etching solutions include solutions containing diamine (e.g., ethylenediamine) and / or triamine (e.g., diethylenetriamine) as bi- and ternary complexing agents, respectively, and hydrogen peroxide as the oxidizing agent. In some embodiments, the etching solution further comprises a pH adjusting agent such as sulfuric acid, amino acid, and carboxylic acid. |