We have developed a new method of accurately profiling a mask shape by utilizing a Mask CD-SEM.
The method is intended to realize high accuracy, stability and reproducibility of the Mask CD-SEM
adopting an edge detection algorithm as the key technology used in CD-SEM for high accuracy CD
measurement. In comparison with a conventional image processing method for contour profiling, it is
possible to create the profiles with much higher accuracy which is comparable with CD-SEM for
semiconductor device CD measurement. In this report, we will introduce the algorithm in general, the
experimental results and the application in practice.
As shrinkage of design rule for semiconductor device has further advanced, an aggressive OPC
(Optical Proximity Correction) is indispensable in RET (Resolution Enhancement Technology). From the
view point of DFM (Design for Manufacturability), a dramatic increase of data processing cost for
advanced MDP (Mask Data Preparation) for instance and surge of mask making cost have become a big
concern to the device manufacturers. In a sense, it is a trade-off between the high accuracy RET and the
mask production cost, while it gives a significant impact on the semiconductor market centered around
the mask business. To cope with the problem, we propose the best method for a DFM solution in which
two dimensional data are extracted for an error free practical simulation by precise reproduction of a real
mask shape in addition to the mask data simulation. The flow centering around the design data is fully automated and provides an environment
where optimization and verification for fully automated model calibration with much less error is
available. It also allows complete consolidation of input and output functions with an EDA system by
constructing a design data oriented system structure. This method therefore is regarded as a strategic
DFM approach in the semiconductor metrology.