| 摘要 |
The present invention relates to a chemical mechanical polishing apparatus. The chemical mechanical polishing apparatus comprises: a grinding surface plate whose upper surface is coated with a polishing pad; a polishing head for contacting the plate of a wafer to press the same during the chemical mechanical polishing process, having a retainer ring including a first member made of conductive substances with a first end surface and a second end surface having a different height around the wafer and a second member contacting the polishing pad during the chemical mechanical polishing process, made of non-conductive substances at the lower part of the first member; a width sensor applying current signals to the wafer to acquire information about the width of the paper; and a control unit for acquiring the width of a wafer polishing layer by reflecting the information about the width of the polishing pad from a third output signal, by acquiring the third output signal from the polishing layer of the wafer from the parts of the width sensor and acquiring information about the width of the polishing pad from a second output signal, at the first and second ends, from parts of the width sensor. Therefore, by reflecting changes in the width of the polishing pad on the width of the conductive layer of the wafer computed from eddy current output signals, the chemical mechanical polishing apparatus is capable of precisely measuring the width of the conductive layer of the wafer, considering the abrasion loss of the polishing pad. |
