Submicron Non-contact Simultaneous Infrared and Raman Spectroscopy for Challenging Failure Analysis

Abstract

We introduce a new infrared (IR) technique that provides submicron spatial resolution by making use of an infraredvisible, pump-probe arrangement that also offers a simultaneous Raman measurement in formerly challenging failure and contamination analyses. These challenges are typically due to the lack of spatial resolution and sample preparation restrictions from conventional FTIR, plus auto-fluorescence (AF) from Raman spectroscopy. Such a combined Optical PhotoThermal InfraRed (O-PTIR) and Raman instrumentation offers spatial resolution improvement over conventional IR measurements by 30 times at 1000 cm-1. The technique also improves sensitivity to exceptionally small quantities (? 400 femtogram) in reflection mode by sensing the photothermal response arising from absorbing infrared radiation (Fig. 1) [1]. The AF-free O-PTIR technique also delivers constant spatial resolution over the entire mid-IR range due to the use of a fixed wavelength probe beam at 532 nm [2]. Simultaneous Raman confirms and complements the O-PTIR measurements in cases with low AF. We will illustrate three examples that will highlight the advantage of the novel technique commonly observed in the failure and contamination analysis community.