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

fYear

1997

fDate

17-19 Nov 1997

Firstpage

202

Lastpage

207

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Test Symposium, 1997. (ATS '97) Proceedings., Sixth Asian

Conference_Location

Akita

ISSN

1081-7735

Print_ISBN

0-8186-8209-4

Type

conf

DOI

10.1109/ATS.1997.643959

Filename

643959