The physical and chemical characterization of defects and particles on wafer surfaces gives important information on their origin. An effective approach for root-cause determination of wafer surface particle problems is to perform both high-resolution images and chemical characterization on individual defects. The traditional root-cause analysis technique used in the semiconductor industry is Scanning Electron Microscopy combined with Energy Dispersive X-Ray Spectroscopy (SEM/EDX). This technique provides high-resolution images and the atomic composition of the defects. However, this is sometime insufficient to fully characterize them and to determine their origin. In this case, the identification of the molecular composition of the defects can help determine their origin.

Optical spectroscopy, such as Infrared and Raman spectroscopy, is a powerful method for determining the molecular composition of many substances. Micro-FT-IR spectroscopy can characterize semiconductor particles only down to 10 μm because of the IR wavelength diffraction limit. Micro-Raman spectroscopy, instead, can provide useful molecular information on many organic as well as inorganic species with 1 μm spatial resolution.