Journal of Micro/Nanolithography, MEMS, and MOEMSQuantitative scanning electron microscope measurement of resistance of incomplete contact holes in ultralarge scale integrated devices
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A method for measuring quantitative resistance of incomplete contact holes in ultralarge scale integrated devices—which uses the brightness of voltage contrast in scanning electron microscope (SEM) images—was proposed. The voltage contrast between a contact hole and the surrounding SiO2 surface was observed by both high and low electron-beam-current SEMs and compared with the resistance of that contact hole measured by a nanoprober. The relationship between the SEM-image brightness and the contact-hole resistance was analyzed theoretically by voltage-contrast simulation based on time-differential equations. It was found that the brightness, within 0〈log(RIp)<3, is proportional to log(RIp), where R is the contact resistance and Ip is the irradiating electron-beam current. It is thus concluded that resistance of incomplete contact holes can be determined quantitatively by utilizing the relationship between SEM-image brightness and the contact-hole resistance.