Influence of the electrokinetic behaviors of abrasive ceria particles and the deposited plasma-enhanced tetraethylorthosilicate and chemically vapor deposited Si₃N₄ films in an aqueous medium on chemical mechanical planarization for shallow trench isolation

Abstract

The effects of the electrokinetic behavior of abrasive ceria particles suspended in an aqueous medium and the deposited plasma-enhanced tetraethylorthosilicate (PETEOS) and chemical vapor deposition (CVD) Si3N4 films on chemical mechanical planarization (CMP) for shallow trench isolation were investigated. The colloidal characteristics of ceria slurries, such as their stability and surface potential, in acidic, neutral, and alkaline suspensions were examined to determine the correlation between the colloidal properties of ceria slurry and CMP performance. The surface potentials of the ceria particles and the PETEOS and CVD Si3N4 films in an aqueous suspending medium were dependent on the pH of the suspending medium. The differences in surface charges of ceria particles and the PETEOS and CVD Si3N4 films have a profound effect on the removal rate and oxide-to-nitride selectivity of CMP performance.

The Effect of the physico-chemical properties of cellulosic polymers on the Si wafer polishing process

“…It is of interest that there was no significant difference of the surface forces between the tip and film, even in the presence of CMC, which indicated that as a result of the electrostatic repulsion between CMC and the Si wafer surface, CMC was only slightly adsorbed onto the Si wafer surface. At alkaline pH, the carboxylic acid of CMC is almost fully ionized and CMC has an extendedchain configuration [18]. Therefore, it was suggested that the formation of a hydro-plane on the Si wafer surface did not take place using the suspension prepared with CMC.…”

Particulate Science and Technology in the Engineering of Slurries for Chemical Mechanical Planarization

“…Ceria slurries are commonly stabilized by water soluble polymers such as poly methylacr ylate acid (PMMA) and poly acrylic acid (PAA) for dielectric CMP [26)]. The adsorption of these polymers is believed to increase the zeta potential of ceria abrasives in neutral and alkaline pH range from 6 to 9 [27)]. This increase in the zeta potential of ceria abrasives is understood to be due to ionization of the polymeric molecules to form negatively charged macromolecules with increase in pH of the solution.…”

“…This increase in the zeta potential of ceria abrasives is understood to be due to ionization of the polymeric molecules to form negatively charged macromolecules with increase in pH of the solution. Kim et al found that ceria slurries, containing 1 % abrasives and 1 % PMMA, were very well dispersed in neutral and alkaline conditions with narrow particle size distribution from 0.01 to 1 µm [27)]. By contrast, the same dispersion in acidic pH condition was observed to be unstable with a large agglomeration of particles and a wide size distribution ranging from 0.02 to 100 µm.…”

Síntese e propriedades fotoluminescentes do óxido de cério dopado com magnésio

“…O óxido de cério é de grande importância por suas propriedades ópticas, alta estabilidade térmica, condutividade elétrica e difusividade, e a capacidade para armazenar e liberar oxigénio. Por estas propriedades, o CeO 2 pode ser utilizado como abrasivo [2], pigmento [3], material de catálise [4], eletrólito sólido de condução de íons oxigênio [5], e sensor de oxigênio [6]. Nos últimos anos foram realizadas algumas tentativas para a preparação de óxido de cério dopado com íons terras raras por várias técnicas, tais como pirólise [7], síntese solvotérmica [8,9], síntese sonoquímica [10], coprecipitação de dois estágios [11,12], processo sol-gel [13,14], reações de estado sólido [15], irradiação por micro-ondas [16], etc.…”