| Popis: |
The faculties of current alignment sensors for CMP processes are studied. The alignment sensors are LSA, LIA and FIA, and all of them are currently equipped on Nikon's NSR series. The results showed that those sensors have enough faculties for present CMP processes. For much progressed CMP technologies, we have experimentally made a new alignment sensor and examined it. The new sensor is based on the `Phase Contrast Microscope' and is made by modifying the FIA optics. By using the new sensor, a mark with only 20 nm step height can be clearly detected with higher accuracy than conventional FIA, and the sufficient possibilities of the new concept alignment sensor for the `progressed CMP process' are confirmed. |
