Low dose charged particle metrology system

Abstract

Systems and methods for conducting critical dimension metrology are disclosed. A charged particle beam apparatus generates a beam for imaging a first area 540 and a second area 541-547. Measurements are acquired corresponding to a first feature in the first area, and measurements are acquired corresponding to a second feature in the second area. The first area and the second area are at separate locations on a sample. A combined measurement is calculated based on the measurements of the first feature and the measurements of the second feature.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Application 62 / 570624, filed October 10, 2017, the entire contents of which are incorporated herein by reference. technical field [0003] The present disclosure relates generally to the field of charged particle beam imaging, and more particularly, to systems and methods for charged particle metrology. Background technique [0004] Charged particle beam metrology systems are used in process control of several semiconductor manufacturing processes. For example, a critical dimension scanning electron microscope (CD SEM) can be used as a dedicated system for measuring the dimensions of fine patterns formed on semiconductor wafers. In order to determine whether a particular CD SEM can be adapted to control a particular process, high accuracy and precision are necessary. High-resolution SEM tools have been established as the standard for direct CD measurements in many advanced semi...

AI Technical Summary

Problems solved by technology

However, there is a trade-off relationship between electron energy dose and signal-to-noise ratio (SNR)

For example, reducing the landing energy may produce SEM images of insufficient quality to make measurements

Therefore, the limitation faced by related art systems is that the landing energy cannot be reduced without a corresponding reduction in image accuracy

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