Detecting Defects in Cu Metallization Structures by Electron-Beam Wafer Inspection

Matsui, Miyako; Zhang, Cheng; Nozoe, Mari; Torii, K.

doi:10.1149/1.1723502

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…In particular, the authors have already reported that the grayscale of such SEM images depends on the variation in defect resistance due to an incomplete contact. [2][3][4][5] The prospective process flow applying our developed in-line resistance inspection using a noncontact type SEM inspection system is shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of voltage contrast in scanning electron microscope images for in-line resistance inspection of incomplete contact

Matsui

Yano

Odaka

et al. 2012

J. Micro/Nanolith. MEMS MOEMS

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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.

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Section: Introductionmentioning

confidence: 99%

Quantitative measurement of voltage contrast in scanning electron microscope images for in-line resistance inspection of incomplete contact

Matsui

Yano

Odaka

et al. 2012

J. Micro/Nanolith. MEMS MOEMS

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“…Electron beam (EB) inspection based on scanning electron microscopy (SEM) is useful to detect the hidden defects causing electrical failure such as contact failure, under-layer electric short, and leakages using voltage contrast [1][2][3][4]. It is difficult for those defects to be detected by optical wafer inspection tools.…”

Section: Introductionmentioning

confidence: 99%

Interval Scan Inspection Technique for Contact Failure of Advanced DRAM Process using Electron Beam-Inspection System

Oh¹,

Kwon²,

Mun³

et al. 2012

JSTS:Journal of Semiconductor Technology and Science

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Abstract-We have developed a highly sensitive inspection technique based on an electron beam inspection for detecting the contact failure of a poly-Si plugged layer. It was difficult to distinguish the contact failure from normal landing plugs with high impedance. Normally, the thermal annealing method has been used to decrease the impedance of poly-Si plugs and this method increases the difference of charged characteristics and voltage contrast. However, the additional process made the loss of time and broke down the device characteristics. Here, the interval scanning method without thermal annealing was effectively applied to enhance the difference of surface voltage between well-contacted poly-Si plugs and incomplete contact plugs. It is extremely useful to detect the contact failures of non-annealed plug contacts with high impedance.

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“…In addition, SEM inspection using voltage contrast has the capability to detect electrical defects (such as incompletecontact defects) and shorts, for example. In particular, the authors have already reported that the grayscale of such SEM images depends on the variation of defect resistance due to an incomplete contact [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of voltage contrast in SEM images for in-line resistance inspection of incomplete contact

2011

Self Cite

View full text Add to dashboard Cite

An in-line inspection method for estimating defect resistances from the grayscale of voltage contrast in 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 taking the variation of defect resistance into account, which strongly depends on the differential voltage between the plug surfaces and the backside wafer. The defect resistances were obtained from the measured I-V characteristics of the deliberately formed 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 inspected patterns was calculated from the improved circuit simulator. Finally, the inspection method was applied to estimate the resistance of defects formed on an SRAM pattern. The calculated calibration curve was used to accurately estimate the defect resistance (with an accuracy of about an order of magnitude) from the voltage contrast formed on the defects in the inspected SRAM patterns.

show abstract

Detecting Defects in Cu Metallization Structures by Electron-Beam Wafer Inspection

Cited by 5 publications

References 7 publications

Quantitative measurement of voltage contrast in scanning electron microscope images for in-line resistance inspection of incomplete contact

Quantitative measurement of voltage contrast in scanning electron microscope images for in-line resistance inspection of incomplete contact

Interval Scan Inspection Technique for Contact Failure of Advanced DRAM Process using Electron Beam-Inspection System

Quantitative measurement of voltage contrast in SEM images for in-line resistance inspection of incomplete contact

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