Hitachi-High-Technologies Corporation

Yuki Ojima

Akira Ikegami

Hideyuki Kazumi

Minoru Yamazaki

Kazunari Asao

Manabu Yano

Takeshi Mizuno

Maki Tanaka

Chie Shishido

Hidetoshi Morokuma

Wataru Nagatomo

Satoru Iwama

An object of the present invention is to provide a scanning electron microscope suitable for monitoring apparatus conditions of the microscope itself, irrespective of the presence of charge-up, specimen inclination, and the like. In order to achieve the object, proposed is a scanning electron microscope including a function to monitor the apparatus conditions on the basis of information obtained with an electron beam reflected before reaching a specimen. Specifically, for example, while applying a negative voltage to the specimen to reflect the electron beam before the electron beam reaches the specimen, and simultaneously supplying a predetermined signal to a deflector for alignment, the scanning electron microscope monitors changes of the detected positions of the reflected electrons of the electron beam. If the above-mentioned predetermined signal is under the condition where an alignment is properly performed, the changes of the detected positions of the electrons reflect deviation of an axis.

Scanning electron microscope

For the purpose of repeatedly observing the bottom of a contact hole with a high aspect ratio, the potential of an electrostatic charge in each of a pattern to be observed and a vicinity of a range to be observed is stabilized by pre-charging a range on which to irradiate a beam of electrons while changing the range on a step-by-step basis.

Observation method with electron beam

In monitoring of an exposure process, a highly isolative pattern greatly changed in a shape of cross section by fluctuations in the exposure dose and the focal position is an observation target. Especially, to detect a change in a resist shape of cross section from a tapered profile to an inverse tapered profile, one of the following observation methods is employed to obtain observation data: (1) a tilt image of a resist pattern is imaged by using tilt imaging electron microscopy, (2) an electron beam image of a resist pattern is imaged under imaging conditions for generating asymmetry on an electron beam signal waveform, and (3) scattering characteristic data of a resist pattern is obtained by an optical measurement system. The observation data is applied to model data created beforehand in accordance with the exposure conditions to estimate fluctuations in the exposure dose and the focal position.

Method of monitoring an exposure process

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Mito, Japan

Yuki Ojima