Patent ID: 7629265

Claim:
A cleaning method used in a semiconductor device manufacturing process, comprising: providing a stack structure of a semiconductor device, including a contact plug within an opening in a dielectric layer, a metal barrier layer between the dielectric layer and the contact plug in the opening, and extending along an upper surface of the dielectric layer with a first thickness having an exposed upper surface, the contact plug having a top excess portion that extends from the opening of the dielectric layer and above the exposed upper surface of the metal barrier layer that extends along the upper surface of the dielectric layer; contacting a surface of the stack structure with a cleaning solution comprising hydrogen peroxide (H 2 O 2 ) and ammonium hydroxide (NH 4 OH) to oxidize and remove the top excess portion of the contact plug; and contacting the surface of the stack structure with dilute hydrofluoric acid (DHF) to remove any residual portions of the oxidized top excess portion of the contact plug, wherein the contacting steps remove the top excess portion of the contact plug to a position substantially level with the upper surface of the metal barrier layer at the first thickness and clean the surface of the stack structure while retaining a substantial portion of the contact plug within the opening of the dielectric layer.