Yield Improvement Using Cryogenic Aerosol for BEOL Defect Removal

A dry, cryogenic aerosol has been integrated into an advanced copper low k dielectric process flow for defect removal. The cryogenic aerosol is able to remove particulate defects from the exposed substrate materials without etching, charging or altering the conducting or insulating properties of the exposed materials. In this work, the cryogenic aerosol is composed of a mixture of argon and nitrogen. The results have confirmed high defect removal efficiency ultimately resulting in a yield increase. The application of a wet clean was not possible without adverse, yield decreasing side effects. Three BEOL processing steps will be covered in this work. The three steps are defect removal after via etch, film deposition, and in-line electrical probe.