Super-Resolution Fluorescence Imaging for Semiconductor Nanoscale Metrology and Inspection.

The increase in the number and complexity of process levels in semiconductor production has driven the need for the development of new measurement methods that can evaluate semiconductor devices at the critical dimensions of fine patterns and simultaneously inspect nanoscale contaminants or defects. However, conventional optical inspection methods often fail to resolve device patterns or defects at the level of tens of nanometers required for device development owing to their diffraction-limited resolutions. In this study, we used the stochastic optical reconstruction microscopy (STORM) technique to image semiconductor nanostructures with feature sizes as small as 30 nm and detect individual 20 nm-diameter contaminants. STORM imaging of semiconductor nanopatterns is based on the development of a selective labeling method of fluorophores for a negative silicon oxide surface using the charge interaction of positive polyethylenimine molecules. This study demonstrates the potential of STORM for nanoscale metrology and in-line defect inspection of semiconductor integrated circuits.

Fast, exact, and non-destructive diagnoses of contact failures in nano-scale semiconductor device using conductive AFM.

We fabricated a novel in-line conductive atomic force microscopy (C-AFM), which can analyze the resistive failures and examine process variance with an exact-positioning capability across the whole wafer scale in in-line DRAM fabrication process. Using this in-line C-AFM, we introduced a new, non-destructive diagnosis for resistive failure in mobile DRAM structures. Specially, we focused on the self-aligned contact (SAC) process, because the failure of the SAC process is one of the dominant factors that induces the degradation of yield performance, and is a physically invisible defect. We successfully suggested the accurate pass mark for resistive-failure screening in the fabrication of SAC structures and established that the cause of SAC failures is the bottom silicon oxide layer. Through the accurate pass mark for the SAC process configured by the in-line C-AFM analyses, we secured a good potential method for preventing the yield loss caused by failures in DRAM fabrication.

Determination of the absolute thickness of ultrathin Al2O3 overlayers on Si (100) substrate.

The thickness of nanometer Al(2)O(3) films was studied by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The thickness was determined from mutual calibration of the XPS and TEM measurements. The thickness offset of Al(2)O(3) films was proved to be close to zero by in situ XPS analysis. The thicknesses of a series of Al(2)O(3)/Si (100) films with different Al(2)O(3) thicknesses could be determined by mutual calibration from the thicknesses measured by TEM and XPS. The electron attenuation length of the Al 2p electron was determined as 2.4334 nm in the Al(2)O(3) matrix.