Title :
A new auto-focus method in critical dimension measurement SEM
Author :
Komatsu, F. ; Motaki, H. ; Miyoshi, M.
Author_Institution :
Integrated Circuit Adv. Process Technol. Dept., Toshiba Corp., Yokohama, Japan
Abstract :
We have developed a new auto-focus method using the image processing technology. This method consists of two steps. The first step is the preset of the objective lens condition with the feedback of Z-sensor. In the second step, the pattern recognition of a target hole pattern is performed prior to auto-focusing scan in order to scan E-beam accurately over the pattern. The measurement repeatability (3σ) can be achieved within 3.9 nm. The pass rate of 98.7% can be realized in the present auto-focus method
Keywords :
automatic test equipment; electron beam focusing; electron lenses; feedback; image processing; image processing equipment; pattern recognition; scanning electron microscopy; spatial variables measurement; 3.9 nm; E-beam; SEM; Z-sensor; auto-focusing scan; autofocus method; critical dimension measurement; feedback; measurement repeatability; objective lens; pass rate; pattern recognition; target hole pattern; Capacitance; Control systems; Electrostatics; Feedback control; Image processing; Integrated circuit measurements; Integrated circuit technology; Lenses; Pattern recognition; Performance evaluation;
Conference_Titel :
Test Symposium, 1997. (ATS '97) Proceedings., Sixth Asian
Conference_Location :
Akita
Print_ISBN :
0-8186-8209-4
DOI :
10.1109/ATS.1997.643959
