Chemical-mechanical polishing (CMP), is a technique used in semiconductor
fabrication for planarizing a wafer or other substrates. This removes material and
tends to even out any irregular topography, making the wafer flat or planar at the
Angstrom level.
Cerium(IV) oxide, also known as ceria, is an oxide of the rare earth metal cerium. It
is known to have a high polishing efficiency for oxide film, but also it has an
unfavourable reputation for problems linked to its quick sedimentation and
agglomeration of particles, which can alter significantly the CMP process, leaving
unwanted defects. Therefore it is necessary to tailor the ceria slurry in order to reach
the right stability requirements for CMP applications.
Polymeric dispersants are typically used to stabilise ceria particles, via steric
stabilisation. Hence, the molecular weight of the dispersant plays a key role in the
stability efficiency.
