Complex device designs make the removal of ashed polymers extremely difficult. In fact, multiple steps are often needed to effectively clean lines and vias of problem debris.
To optimize this cleaning, aqueous-based detergent formulations, used as a rinse step, may be added in between residue cleaning to enhance efficacy. Also, after using a concentrated water-soluble solvent formulation to remove complex post-etch/ash contaminants, the organic/solvent film must then be exposed to a non-corroding, non-contaminating rinse, using a spray unit or immersion tank. Low foaming chemistry is preferable when using a spray unit, but not as important in megasonic immersion cleaning.
Intersurface Dynamics manufactures detergents for the removal of organic/solvent films left by ash residue removers. These detergents are used in highly dilute concentrations, during or after the residue removal step, to eliminate any organic and to protect against corrosion of copper or aluminum structures.