Communication—Effect of Hydrogen Water on Ceria Abrasive Removal in Post-CMP Cleaning

Abstract

In the present study, hydrogen water was applied to ceria abrasive removal in post-CMP cleaning. The surface of the ceria abrasive was reduced by the hydrogen water from the Ce4+ to Ce3+ state. Reduction of the ceria abrasive can weaken the bonding between ceria and the SiO2 wafer surface. X-ray photoelectron spectroscopy (XPS) and UV–visible observations were utilized to reveal the reduction from Ce4+ to Ce3+ by hydrogen water. Thus, the remaining ceria particles and Ce-ion concentrations were reduced by 70% and 63%, respectively.

Development of a pH-independent Post-CMP Cleaning Solution using Phosphoric Acid-based Surfactants for Removal of Ceria Nanoparticles

“…Recently, significant attention is drawn to develop a cleaning technology that removes ceria nanoparticles from a SiO 2 surface by selectively breaking the Ce-O-Si bond, while minimizing the loss of SiO 2 . 6,7,22 A few studies have been conducted to break this bond using hydrogen peroxide (H 2 O 2 ), thereby improving the cleaning efficiency. 7,22 A study reported that a sulfuric acid peroxide mixture (SPM) effectively removed the chemically-bound ceria nanoparticles from a SiO 2 surface without any loss of SiO 2 .…”

“…6,7,22 A few studies have been conducted to break this bond using hydrogen peroxide (H 2 O 2 ), thereby improving the cleaning efficiency. 7,22 A study reported that a sulfuric acid peroxide mixture (SPM) effectively removed the chemically-bound ceria nanoparticles from a SiO 2 surface without any loss of SiO 2 . 21 Furthermore, it is crucial to prevent the re-adsorption of the removed nanoparticles.…”

Communication—A Novel Method to Improve Cleaning Performance by Removing Small Particles in CMP Slurry

“…3 These contaminants can cause circuit defects on the wafer, 4 and various cleaning methods have been suggested to improve post-CMP cleaning. [5][6][7] Recently, it has been reported that small ceria particles remaining on the silicon dioxide wafer are difficult to remove after polishing. 8,9 In addition, problems with agglomeration of slurry particles by shear-induced which can affect to slurry stability have been reported in the CMP process.…”