EAG Application Solutions for Cleanliness

Cleanliness is defined by how clean a surface is, so it is effectively the opposite of contamination. Assessing cleanliness often involves comparing samples that were processed differently or exposed to different environments. The relative differences between the test and control or reference samples can supply useful information about factors that affect surface cleanliness. In cleaning processes, for example, sensitive measurements may reveal that cleaning chemicals left residues because they were not rinsed properly.

In general, assessing cleanliness requires you have some idea what you are trying to find. Are you looking for elemental or molecular contaminants? Do you want to confirm their presence or absence? Or do you want to know whether they are below a certain level?

Investigating very clean surfaces may require techniques that have detection limits in the parts-per-million range, such as Total Reflection X-ray Fluorescence (TXRF), which looks at elemental contaminants only, and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), which looks at both elemental and molecular contaminants. In cases where cleanliness is measured by how many particles are on the surface, Scanning Electron Microscopy (SEM) is a good option, as it can involve surface imaging and particle counting.

Primary Analytical Techniques

• GC/MS
• SEM
• TOF-SIMS
• TXRF
• X-ray Photoelectron Spectroscopy (XPS) and Electron Spectroscopy for Chemical Analysis (ESCA)

Secondary Analytical Techniques

• Auger Electron Spectroscopy (Auger)
• Fourier Transform Infrared Spectroscopy (FTIR)
• Gas Chromatography (GC) and Mass Spectrometry (MS)

Application Notes