| 摘要 |
PROBLEM TO BE SOLVED: To analyze the characteristics of periodic structures formed on a sample on a real time basis. SOLUTION: A spectroscopic measurement module is provided which generates output signals as a function of wavelength. The output signals are supplied to a processor, and the processor creates an initial theoretical model having a rectangular structure. The processor then calculates the theoretical optical response of that sample to broad band radiation. The calculated optical response is compared to normalized measured values at each of a plurality of wavelengths. Based on the comparison, the model configuration is modified to be closer to the actual measured structure. The processor recalculates the optical response of the modified model and compares the calculation result with the normalized data. This process is repeated in an iterative manner until a best fit rectangular shape is achieved. Thereafter, the complexity of the model is iteratively increased, by dividing the model into layers each having an associated width and height. The model is fit to the data in an iterative manner until a best fit model is obtained which is similar in structure to the periodic structure. COPYRIGHT: (C)2011,JPO&INPIT |
