Electrical defect SEM review under the various electric circumstances on SAC layer

Le résumé fourni par la source

Traditionally the defects, detected by inspection tools (optic & EBI), have been reviewed through DR-SEM or CD-SEM. Nevertheless, when physical defects are characterized using conventional in-line SEM it is hard to re-detect electrical defects because of the restricted working range in e-beam control. To detect and review electrical defects on contact layer EBI tools were used due to the in-line SEM limitation on electrical defect reviews. However the quality of the image was not acceptable to characterize type of defects due to its low resolution (20~30nm). In this article, the review condition of electrical defect was studied under the various electric conditions on Self Align Contact (SAC) layer. In order to achieve the optimum condition, a wide range of negative and positive conditions were applied using acceleration voltage, I-probe current, cap voltage and scan rate. Under stable weak negative charge conditions, 100% review of electrical and contact bottom defects were achieved. Furthermore, we found the high I-probe current and the appropriate acceleration voltage are main factors which increase the capability to re-detect the electrical defect. In this article, we figure out which defect is electrical defect and non-electrical defect applying to diverse electric conditions on the wafer.

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