No abstract

Non-contact electrical metrology offers a fast and cost saving monitoring of dielectrics in IC manufacturing process. This corona-Kelvin measuring technique has entered the maturity stage with about 400 tools installed in silicon IC-fabs. We discuss recent advancements that broaden the spectrum of monitoring parameters and enhance the precision of these measurements. We also discuss the current ongoing extension of corona-Kelvin metrology to the micro scale measurement on sites as small as 30µm x 30µm. This opens new possibilities for non-contact electrical testing of product wafers, rather than expensive process monitor wafers. Micro-measurement is illustrated using flash memory ONO structures and corona induced programming and erasing.

No abstract

Kelvin-probe surface voltage mapping, SVM, on epitaxial SiC, charged with corona into deep depletion, reveals SV defects manifested as spots with decreased surface voltage. For 150μm thick epi-layer, SV defects coincide with low carrier lifetime spots revealed by microwave detected photoconductance decay, μPCD. In the photoluminescence image, these defects are seen as triangular dark spots, described in literature as stacking-fault related triangular defects. For thin epi-layers (2.2μm), defects are visible only in SVM. In this case, high resolution SVM performed with Kelvin Force Microscopy identifies a triangular defect shape. Two mechanisms are proposed, accounting for SV defects. For high intensity defects exhibiting large magnitude fast decreasing voltage, the probable mechanism is defect related leakage; causing neutralization of corona surface ions. Low intensity defects can be explained considering deep level emission. The latter mechanism has been investigated using SV transient and spectral analysis analogous to isothermal DLTS and Laplace DLTS.

No abstract