Introducing novel NMT technology for ultra-thin film measurement

In the semiconductor industry, 3D stacking leads the race to miniaturizing devices at a competitive cost. Thin films are becoming ultra-thin and more localized, and feature wider material variations and smaller scales interactions with less tolerance to aberrations.

By Roni Peretz, Benny Donner, Colin Smith and Michael Geffen

NMT: a new generation of XRF technology

XwinSys has identified the semiconductors recent market trends and has developed a novel XRF technology accordingly, named NMT: Noise-reduced Multilayer Thin-film measurement. This innovative approach can be used for in-line inspection and metrology features, to accurately and precisely analyze single and multi-layered elements in ultra-thin films, down to 1Å.

Figure 1: XwinSys Onyx System
XwinSys Onyx System

Overcoming EDXRF weaknesses

The NMT concept significantly improves the S/N ratio, resulting in low background noise by using a set of unique Silicon Drifted Detectors (SDD), replacing the air atmosphere with helium, implementing a-spot vertical incident X-ray beam and applying unique background removal algorithms.

XwinSys XRF Module
Figure 2: XwinSys XRF Module

Free from optical constants

When using common optical techniques to analyze layer’s thickness below 50Å, calculation constants (D, N, K) are necessary but also highly unpredictable; In a multi-layer stack the values of these constants are even more challenging to analyze. X-ray is not sensitive to these constants, hence direct results of ultra-thin layers (both opaque and transparent materials) can be accurately valued by the NMT.

Layers Structure of Ultra-Thin Film
Figure 3: Layers Structure of Ultra-Thin Film

NMT novel technology can be utilized for in-line applications ranging from localized ultra-thin film stacks to the inspection of 3D localized features to the analysis of defects involving geometries, voids and material elements.