Teachers in England and the United States—the Background

Kelsall, R. K.; Kelsall, Helen M.

doi:10.1016/b978-0-08-006519-9.50005-3

Cited by 2 publications

(3 citation statements)

References 4 publications

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“…Indeed, this DADMAC layer can prevent the interaction between the oxide surface being polished and the ceria abrasives as suggested by Kang et al 15,16,26 and Shimono et al 23 Also, while the adsorption of DADMAC on ceria particles is low and can be considered weak (see below), it can lower the oxide RRs if it reduces the number of reactive species on the ceria surface. 23,[27][28][29][30] Adsorption strength of DADMAC on SiO 2 and CeO 2 abrasives.-The measured zeta potentials of 1 wt% of silica (d mean ≈ 85 nm) and 1 wt% of ceria (d mean ≈ 140 nm) particles both in dispersions without DADMAC are −46.4 mV and +73.5 mV, respectively (Fig. 5).…”

Section: Resultsmentioning

confidence: 97%

“…Proposed mechanism for the observed non-prestonian removal rates.-Ceria particle dispersions without any additives yield high oxide RRs, as reported by several authors. 19,23,24,27,[29][30][31]37,38 Several of these authors proposed that the Ce 3+ species on the surface of ceria particles are responsible for the high oxide RRs by creating strong Ce-O-Si bonds at the surface which cause rupture of the weaker underlying Si-O-Si bonds resulting in material removal during polishing.…”

Section: Resultsmentioning

confidence: 99%

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Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Korkmaz

Babu

2014

ECS J. Solid State Sci. Technol.

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A slurry with a non-Prestonian dependence on the polishing pressure can help in minimizing dishing and erosion during shallow trench isolation chemical mechanical planarization. Here, we show that ceria-based slurries containing diallyldimethylammonium chloride (DADMAC) yield a non-Prestonian blanket film polish rate with a low threshold pressure (1-2 psi) when polishing plasma-enhanced chemical vapor (PECVD) tetraethylorthosilicate (TEOS) deposited oxide as well as thermal oxide films. The polishing mechanism of this non-Prestonian slurry was investigated by a series of experiments involving zeta potential measurements, thermogravimetric analysis (TGA) and UV-vis spectroscopy and it was shown that more DADMAC molecules are adsorbed on silica particles (as oxide film representatives) than on ceria particles and the binding strength between DADMAC and silica is much higher than that with ceria surface. Shallow trench isolation (STI) is an ubiquitous complimentary metal-oxide semiconductor isolation process technology. Deposition of an isolation stack that contains 3 to 10 nm thick 1,2 thermally grown pad oxide on top of a silicon substrate followed by the deposition of either plasma-enhanced chemical vapor deposition (PECVD) or low-pressure chemical vapor deposition (LPCVD) nitride layer (10 to 30 nm) 1 is the first step in the STI process. In the next step, active areas and isolation fields are determined by patterning the silicon nitride and silicon dioxide pad layers on the silicon substrate, followed by etching of trenches into the silicon substrate using the oxide/nitride stack as a mask. The trenches are then filled with oxide, employing high density plasma-enhanced chemical vapor deposition (PECVD) process using tetraethylorthosilicate (TEOS) as the source of silicon, because of its high gap-filling capacity. The deposited oxide not only fills the trenches but also generates an overfill, which needs to be removed. This is achieved through planarization of the oxide film topography by chemical mechanical planarization (CMP) using a slurry that produces a high oxide and very low nitride removal rates (RRs).In this STI process, major concerns include dishing within the oxide features resulting from over-polish as well as the erosion of the underlying nitride film and, in some cases, the details of the corner rounding near active areas. Therefore, optimization of the CMP process is crucial in order to achieve complete removal of the oxide on top of the nitride film with good planarity and uniformity and to avoid erosion and dishing during the CMP process. 3,4 One method that can be used to minimize dishing and erosion during STI CMP is to control the polishing performance by using a slurry that shows a non-Prestonian polishing behavior. Non-Prestonian behavior occurs when there is a non-linear relationship between applied polishing pressures and resulting polishing rates. Here we consider only the effect of pressure and not that of the rotational velocity on the blanket film polish rates.Several models were di...

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Korkmaz

Babu

2014

ECS J. Solid State Sci. Technol.

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“…The lead dioxide electrode has been used extensively in electroorganic synthesis due to its advantages of a high oxygen overvoltage, inertness to most chemical reagents, and low cost. Numerous reports and patents have appeared in the literature (8)(9)(10) for the preparation of lead dioxide electrodes. According to some reports (11), the alpha-crystal form of lead dioxide is obtained from an alkaline electrolyte and has been found to be superior in quality to the beta-crystal form obtained from an acidic electrolyte.…”

Section: Anode For Electrolytic Production Of Anthrasol Blue Ibcmentioning

confidence: 99%

Preparation of Anthrasol Blue IBC by Anodic Oxidation

Hui¹

1983

J. Electrochem. Soc.

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as an insulation element between the electrolyzer elements. Its chemical resistance is excellent.Optimization of the diaphragms is still necessary, which includes a more appropriate shape for the holes used in the metal plate. However, it has been shown that an insulating coating may be obtained that does not clog the plate holes and that helps in decreasing power consumtion within the system. ABSTRACTThe use of anodic oxidation for preparation of Anthrasol Blue IBC eliminates totally the oxidant lead dioxide and results in the solution of the complicated problems arising in the fields of oxidant recovery and environmental protection.

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Teachers in England and the United States—the Background

Cited by 2 publications

References 4 publications

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Preparation of Anthrasol Blue IBC by Anodic Oxidation

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