Rohm and Haas Electronic Materials, a subsidiary of DowDuPont, had a patent published Feb. 28, 2019 for Aqueous Silica Slurry Compositions for Use in Shallow Trench Isolation and Methods of Using Them. In the course of their work, the inventors sought to verify the size of the particles being used in the chemical mechanical planarization (CMP) slurry with the CPS Disk Centrifuge.
According to the patent application:
“CMP for STI requires the removal and planarization of the silicon dioxide overburden from the isolation areas, thereby resulting in a coplanar surface with the silicon dioxide-filled trenches. In STI, the silicon nitride film surfaces must be cleared of the silicon dioxide or oxide to allow subsequent removal of the nitride hard mask in downstream processing. An acceptable oxide : nitride removal rate ratio is necessary to prevent damage to the underlying Si active areas and provide an overpolish margin to ensure all pattern densities are cleared of the oxide. Further, dishing of the oxide in any trench must be avoided to prevent low threshold voltage leaks in finished gates.”
The Ceria slurries currently favored for most STI CMP are costly and may cause defects during polishing, create process instability, and have issues with removal rate. As such, they have sought to create a silica-based formula that resolves the issues typically experienced when using silica slurries for STI: oxide dishing control and inadequate oxide : nitride selectivity. The inventors used the CPS Disc Centrifuge to complete this valuable work.
Around the world, researchers and inventors rely on CPS Instruments when accuracy matters most. The CPS disc centrifuge provides a higher resolution than light scattering or particle counting methods at a much faster rate of analysis than competitive sedimentation-based particle sizing instruments. Whether replacing an aging system or increasing capacity with a new system, an investment in a CPS disc centrifuge is an investment in consumer confidence. Learn more about our applications here.