With the increasing move towards measurement of smaller and smaller dimensions, the reliability of existing metrology approaches is begin called into question. The most widely used approach for CD measurement in a fabrication environment is the use of Low Voltage Scanning Electron Microscopy. SEMs are routinely used in industry for top-down measurements of lines, spaces, and contacts in the production line. The destructive approach of cross section SEMs is used for trouble shooting and analysis. Electrical CD measurements are also routinely used to measure the CDs of conducting layers in the production environment. However, electrical CD metrology is not appropriate for the majority of surfaces that are non-conductive, such as those with photoresist. It has been speculated for a while n ow that the AFM can provide a viable alternative by overcoming all the drawbacks of the other metrology techniques. This paper address this issue and discusses the relative merits of the AFM as compared to the others. The measurement bias between the three techniques on isolated line features ranging from 0.1 to 0.3 microns is compared. The ability of the AFM to measure profiles is discussed.
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