| 摘要 |
A process for performing CMP in two steps is described. After trenches have been formed and over-filled with copper, in a first embodiment of the invention a hard pad is used initially to remove most of the copper until a point is reached where dishing effects would begin to appear. A soft pad is then substituted and CMP continued until all copper has been removed, except in the trenches. In a second embodiment, CMP is initiated using a pad to which high-pressure is applied and which rotates relatively slowly. As before, this combination is used until the point is reached where dishing effects would begin to appear. Then, relatively low pressure in combination with relatively high rotational speed is used until all copper has been removed, except in the trenches. Both of these embodiments result in trenches which are just-filled with copper, with little or no dishing effects, and with all traces of copper removed everywhere except in the trenches themselves.
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