| 摘要 |
A method of forming a copper via and the resultant structure. A thin layer of an insulating barrier material, such as aluminum oxide or tantalum nitride, is conformally coated onto the sides and bottom of the via hole, for example, by atomic layer deposition (ALD) to a thickness of less than 5 nm, preferably less than 2 nm and having an electrical resistivity of more than 500 microohm-cm. A copper seed layer is then deposited under conditions such that copper is deposited on the via sidewalls but not deposited over most of the bottom of via hole. Instead energetic copper ions sputter the barrier material from the via bottom. Copper is electroplated into the via hole lined only on its sidewalls with the barrier. The invention preferably extends also to dual-damascene structures in which the copper seed sputter process sputters the barrier layer from the via bottom but not the trench floor.
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