High-accuracy development monitoring technology

A development monitor system capable of highly accurate control of pattern width has been established. This system is composed of a unique monitor pattern on the process wafer, the 0th order diffraction light measuring unit, and the image analysis and process control unit. In the conventional development process in which no monitor system is employed, the CD variation in 200nm line width was about 15nm when +/- 5 percent dose error exist. However, using the new system, 1nm of CD variation was obtained. In this article, a high-sensitivity monitor pattern is proposed and its performance in controlling 200nm line and space patterns in the development process is reported.