Integration of a Barrier Layer Overlying Large Copper Pads without Patterning Step
Original Publication Date: 2004-Nov-16
Included in the Prior Art Database: 2004-Nov-16
A novel integration path forming a barrier layer overlying copper has been studied. This integration pertains to large copper areas such as bond pads at the last metal level or metal-insulator-metal (MIM) capacitor structures. For these structures a barrier layer is needed passivating the copper film. In order to reduce cost and process complexity no additional patterning step (photo/etch) is needed for its formation. The barrier is rather formed by immediate deposition on the electroplated and annealed copper film. After chemical-mechanical-polishing (CMP) the barrier is left behind in the large structures only where it is needed. This barrier scheme provides excellent protection for bondpads before aluminum or chromium deposition, and a smooth layer as it is required for MIM capacitors. This paper describes the integration and application of a barrier overlying Cu pads and provides an integration path without additional patterning step.