| 摘要 |
<p>A method and apparatus for processing a semiconductor wafer to reduce CD variation feeds back information gathered during inspection of the wafer to a previously visited processing tool and feeds forward information to adjust the next process the wafer will undergo. The inspection and processing are performed at a single processing module without exposing the wafer to ambient atmospheric conditions. Embodiments include removing a wafer from a wafer cassette, and measuring a dimension of a feature on the surface of the wafer, such as the feature's CD using an optical measuring tool. A process, such as an etch process, is then performed on the wafer using a set of process parameter values, such as an etch recipe, selected based on the CD measurement, and the wafer is returned to a cassette. The CD measurements are also linked to photolithography adjustable parameters such as stepper focus and exposure settings. The linked information on focus and exposure is fed back to the previously visited photo cell so the stepper can be adjusted, either automatically or at the user's discretion, to correct the deviation in following lots. In some embodiments, post-etch processing, such as ash stripping, wet cleaning and/or further CD measurement, are performed by the module before the wafer is returned to a cassette. All of the transfer and processing steps performed by the module are performed in a clean environment, thereby increasing yield by avoiding exposing the wafer to the atmosphere and possible contamination between steps. This feedback and feed-forward mechanism improves CD control by adjusting processing parameters for every wafer based on the wafer's measured CD.</p> |
