CO2 Snow Precision Surface Cleaning
Eco-Snow® 's precision cleaning is a revolutionary technology for removing micron and submicron particulate and organic contamination using carbon dioxide (CO2). Liquid CO2 is expanded through specially designed nozzles to generate a fast-moving stream of solid CO2 "snow" particles and CO2 gas. When aimed at a contaminated surface, the CO2 snow particles dislodge both large and small particles from the surface by a process called momentum transfer. As the particles are detached from the surface, the CO2 snow particles convert into gas and the particles are then carried away in the CO2 gas stream. Thin film organic residues are removed by solvent properties of the solid CO2 snow particles as it impacts the surface of the substrate. Eco-Snow has proven to be effective in removing sub micron particles.
Removing post-etch veils by momentum transfer
Applying a very cold stream of CO2 causes the veil material to shrink and debond from the device features. Further physical pressure of the cryogenic particles breaks any remaining bonds and sweeps the particles off the surface leaving a completely clean, veil free devise.
Removing Particulates by Momentum Transfer
The impact of CO2 Snow dislodges small particles
which are then swept away in the
stream of CO2 gas. The Eco-Snow
cleaning process can remove particles as small as
Metal lift-off by thermal contraction and momentum transfer
The metal layer undergoes a rapid contraction due to the chill of the CO2 spray. The contraction causes film delamination at the interface with the photoresist layer beneath. The CO2 snow peels the metal from the photoresist leaving the desired pattern exposed.
Removing Organic Film by Solvation
When the CO2 Snow impacts a surface contaminated with an organic film, it forms a transient dense phase boundary layer, then it rebounds off the surface carrying the contaminant with it. When the spent CO2 leaves the system it sublimes completely, eliminating the need for drying and for disposal of waste solvents.