The Research Of Key Technology For Micro-Nano Linewidth Measurement On Ultraviolet Microscope

Nowadays in semiconductor integrated circuit fabrication area, the linewidth of transistor has attained 65nm and 32nm, and is in advance towards 22nm even 16nm size. When linewidth shrinks in 10nm magnitude, the measurement will enter the scopes of "critical dimensions" area, which means the measurement accuracies and measurement uncertainties will become a great challenge to current technologies. In order to solve the problem, the National Institute of Metrology in China is researching a metrological ultraviolent optical nanometer geometry structure size measurement standard apparatus for photomask linewidth measuring and traceability. In the dissertation, the microscope autofocus system as well as photomultiplier signal amplification and processing system are discussed in detail to demonstrate the key technologies of nanometer linewidth measurements; after that, the validation and precision of the system are testified through a set of experiences. The work of the dissertation can be divided into some parts as follows:1. By research the overall architecture of metrological ultraviolet optical microscope, the micro-nano linewidth measurement principle based on the photovoltaic effect of photomultiplier is described, and the split light optical path design structure is designed, finally two important electrical control system for linewidth measurement, namely autofocus system and photomultiplier signal amplification processing systems are described.2. The design of linewidth measurement process autofocus system is described. In hardware, includes:the design and selection of hardware architecture, in software, includes the selection of evaluation function the focus window and the search strategy, by comparing the different evaluation function, we ultimately select the evaluation function which based on wavelet. In terms of software, the use of VC and MATLAB mixed programming method can help us simple and effective realization the image wavelet, so as to realize the image definition evaluation.3. The design of photomultiplier signal amplification processing system is described. Through analysis of the light intensity received by the photomultiplier tube, and finally select H11461-09 photomultiplier tube as a photoelectric conversion element module. Since the output signal of the selected photomultiplier tube is a weak current signal, in order to satisfies the needs of the subsequent sampling circuits,a current amplifier circuit is researched based on current negative feedback, and finally the light intensity signal of the line width is converted into an analog voltage signal.4. By combining the previous studies of autofocus system and photomultiplier signal amplification processing system, we build a set of micro-nano line width measurement system. Using this system to scanning measure the standard grid model, finally verified the feasibility and accuratelyof the method which we design for Linewidth measurement by experiment...