| abstract |
Method and system for controllable deposit of copper onto an exposed surface of a workpiece, such as a semiconductor surface. A seed thickness of copper is optionally deposited onto the exposed surface, preferably using oxygen-free liquid ammonia to enhance this deposition. The workpiece exposed surface is then immersed in an electroplating solution, including copper and liquid ammonia at a suitable pressure and temperature, and copper is caused to plat e onto the exposed surface at a controllable rate. When the copper deposited o n the exposed surface reaches a selected total thickness, electroplating is discontinued, the electroplating solution is removed, and the gaseous and liquid ammonia are recovered and recycled for re-use. |