Effects of 50 to 200-keV Electrons by BEASTLI Method on Semiconductor Devices

Fumio MIZUNO  Satoru YAMADA  Tsunao ONO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.3   pp.392-397
Publication Date: 1996/03/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Scientific ULSI Manufacturing Technology)
Category: Device Issues
Keyword: 
semiconductor devices,  wafer inspection,  scanning electron microscope,  high-energy electron beam,  device damage,  surface charging,  BEASTLI,  

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Summary: 
We studied effects of 50-200-keV electrons on semiconductor devices using BEASTLI (backscattered electron assisting LSI inspection) method. When irradiating semiconduc-tor devices with such high-energy electrons, we have to note two phenomena. The first is surface charging and the second is device damage. In our study of surface charging, we found that a net positive charge was formed on the device surface. The positive surface charges do not cause serious influence for observation so that we can inspect wafers without problems. The positive surface charging may be brought about because most incident electrons penetrate the device layer and reach the conducting substrate of the semiconductor device. For the device damage, we studied MOS devices which were sensitive to electron-beam irradiation. By applying a 400- annealing to electron-beam irradiated MOS devices, we could restore the initial characteris-tics of MOS devices. However, in order to recover hot-carrier degradation due to neutral traps, we had to apply a 900- annealing to the electron-beam irradiated MOS devices. Thus, BEASTLI could be successfully used by providing an apporopri-ate annealing to the electron-beam irradiated MOS devices.