A review on chemical and mechanical phenomena at the wafer interface during chemical mechanical planarization

Abstract

Abstract

Piezocatalysis for Chemical–Mechanical Polishing of SiC: Dual Roles of t‐BaTiO3 as a Piezocatalyst and an Abrasive

“…Preston's equation was frequently used to explain the changes of MRR with the rotation speed in CMP technology. According to Preston equation [6] MRR = kp𝜐 (2) where MRR is the material removal rate, k is the Preston coefficient, p is the applied pressure on the wafer surface, and ʋ is the relative velocity between the wafer and the polishing pad. MRR was a linear relationship between MRR and ʋ.…”

“…The difference was possible dependent on piezoelectric effect in piezo-CMP, because the Preston equation was only a classic equation to describe contact mechanics, and did not consider the effect of the piezo-catalysis. [6] For example, according to the following formulae of piezopotential:…”

“…[5] Thus, the ultra-precision polishing has become one of most demanded research topics in the field of advanced materials. [3,6] In the third-generation semiconductors, SiC is a dominant candidate with more excellent characteristics, compared with several state-of-the-art Si materials, such as its wide bandgap (2.3-3.2 eV), high break down field and high thermal conductivity (4.9 W m −1 K −1 ) and thermal stability (3.8 × 10 −6 °C−1 ), high breakdown voltage (1 × 10 6 −5 × 10 6 V•cm −1 ) and low coefficient of thermal expansion (∼1.4 × 10 -6 K −1 ). [3,7] However, its inherent high hardness (Moh's hardness 9.2) and chemical inertness bring many challenges to traditional polishing techniques.…”

Photo-oxidative degradation of polyacids derived ceria nanoparticle modulation for chemical mechanical polishing

“…However, PAA-coated ceria particles are known to undergo transitions of bridging agglomeration-stable-flocculation depending on their physicochemical conditions such as pH, ionic strength, temperature, and concentration 63 . In this case, the polymer interferes with the interaction among particles, so that they do not come into direct contact with each other, however, it is difficult to confirm that the dispersibility of a solution is good due to the bridging agglomeration of nanoparticles by polymers 35 , 64 .…”

“…In this case, the polymer interferes with the interaction among particles, so that they do not come into direct contact with each other, however, it is difficult to confirm that the dispersibility of a solution is good due to the bridging agglomeration of nanoparticles by polymers 35 , 64 . In this experiment, the ceria particles have negative potential because the pH of the slurry was adjusted to 9 63 . The repulsive force between a polymer and a particle surface becomes strong with increasing pH, which hinders the adsorption of polyacids on the ceria surface.…”