Accurate and reliable Critical Dimension (CD) measurement is one of the most important goals of CD metrology. Today, most CD measurements are performed utilizing the Scanning Electron Microscope (SEM). One of the most commonly employed measurement detection algorithms is the Threshold method. This method is most useful for measuring CD when the structure being measured consistently produces stable peaks in the secondary electron induced image intensity profile'3. However, the intensity profile becomes more complicated when there are multiple peaks whose peak heights are neither stable nor fixed in position. In this case, accurate and reliable CD measurements are difficult to achieve. In this paper, a novel technique of pre-dose and re-dose electrical beam treatment will be described. The technique is effective in producing reliable intensity profiles resulting in accurate CD measurements, and the recipe developed using the technique runs fully automated. The technique has been applied in our factory with success.

193 nm resist shrinkage due to critical dimension scanning electron microscope (CD-SEM) measurements is a wellknown but unresolved metrology issue in microlithography. Although there have been numerous studies 1-7 on this subject, there are few publications on the 193 nm resist shrinkage finger-print carried over to etched features, i.e., the CD shrinkage carryover effect. This paper reports the results of our CD-SEM measurement study. We observed that the CD changes due to measurement were still present after etch and were often greater than 15% of the feature size. The shrinkage result implies that the action of CD-SEM measurement is destructive to the patterned circuitry. An improved CD-SEM measurement methodology is required to reduce circuitry damage. The study also revealed that minimal shrinkage carryover (less than 1%) could be obtained when the CD-SEM measurement condition was optimized. These results also indicate that measurement of CD shrinkage on post-etch patterns can offer a very effective method to characterize pre-etch resist shrinkage.