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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Quantitative measurement of voltage contrast in scanning electron microscope images for in-line resistance inspection of incomplete contact
Author(s): Miyako Matsui; Tasuku Yano; Takayuki Odaka; Hiroshi Nagaishi; Koichi Sakurai

Paper Abstract

An in-line inspection method for estimating defect resistances from the grayscale of voltage contrast in scanning electron microscope (SEM) images of manufactured patterns was developed. This method applies a circuit simulator to calculate the intensity of the secondary electrons according to an equivalent-circuit model considering the charge-up voltage on the patterns. To accurately estimate the resistance of defects formed in a device, first, the simulator was improved by considering the variation in defect resistance, which strongly depends on the differential voltage between the plug surfaces and the backside wafer. The defect resistances were obtained from the measured current-voltage (I-V) characteristics of the intentional defect on the standard calibration wafers, in which some incomplete-contact defects were systematically formed. Next, to consider the effect of the electronic characteristics of the pattern under the normal plugs on the grayscale, the I-V characteristics of the normal plugs were measured. The equivalent circuit of the simulator was improved by taking into account the measured I-V characteristics. The calibration curve for the manufactured patterns was calculated from the improved circuit simulator. Finally, the inspection method was applied to estimate the resistance of defects formed on an static random access memory (SRAM) pattern. The calculated calibration curve was used to estimate the defect resistance from the voltage contrast formed on the defects in the manufactured SRAM patterns. The accuracy of the estimation was about an order of magnitude.

Paper Details

Date Published: 7 June 2012
PDF: 8 pages
J. Micro/Nanolith. 11(2) 023008 doi: 10.1117/1.JMM.11.2.023008
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 11, Issue 2
Show Author Affiliations
Miyako Matsui, Hitachi, Ltd. (Japan)
Tasuku Yano, Hitachi, Ltd. (Japan)
Takayuki Odaka, Hitachi, Ltd. (Japan)
Hiroshi Nagaishi, Renesas Technology Corp. (Japan)
Koichi Sakurai, Renesas Technology Corp. (Japan)


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