For high aspect ratio 3D NAND and critical dimension advanced node logic contacts, reliably detecting endpoint well below 1% open area is critical to yield and overall productivity.
End point detection of contact etch through field oxide (silicon dioxide) needs to be performed to minimize contact resistance and ensure a good electrical contact with transistor source or drain, but without excessive over-etch, which can cause shorts to the gate region or substrate damage.
For 3D NAND, etching through hundreds of alternate SiO2 and Si3N4 layers requires high speed quantitative end point detection.
To ensure consistent and optimized contact etch, high sensitivity in-situ molecular diagnostics is needed, to provide real-time measurement and quantification of the etch by-products and to enable a clearly-defined endpoint to be detected.
With reducing contact open area (OA%), legacy metrology solutions like Optical Emission Spectroscopy (OES) lack the sensitivity to accurately detect etch end point.
With OA% sensitivity demonstrated to <0.25%, Aston delivers accurate and actionable detection up to an order of magnitude better than OES (~2.5%).
Learn more about Aston and download our Application Brief below for more details on how Aston supports industry-leading sensitivity in helping to improve end point detection.