| 摘要 |
The invention relates to reducing Focused Ion Beam (FIB) differential sputter rates in crystalline materials. In integrated circuits, copper-based interconnects are beginning to replace aluminum-based interconnects. Unfortunately, FIB sputtering of copper is more difficult than that for known aluminum alloys, because of large changes in milling rates based upon grain orientation. In order to meet the need for an improved milling technique that will lead to more uniform milling of such elements, it is proposed according to the invention to apply a sacrificial layer onto a surface of a crystalline structure followed by the projection of an ion beam onto the applied sacrificial layer, preferably in a repetitive process until the crystalline structure is removed or reduced to a predetermined level, thus increasing uniformity of the removal of the atoms from the surface of the crystalline structure during the projection of the ion beam. |
