Interfacial Reactivity Between Ceria and Silicon Dioxide and Silicon Nitride Surfaces

Carter, Phillip W.; Johns, Timothy P.

doi:10.1149/1.1951203

Cited by 53 publications

(43 citation statements)

References 11 publications

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“…In order to improve the selectivity and uniformity, various additives have been used within slurries such as amino acid [5], SDS surfactants [6]. Although the improvement in the selectivity could be achieved by conventional silica slurry [5,6], ceria abrasives have been widely used in STI CMP due to their high removal rates [8][9][10][11][12]. Moreover, most of ceria slurries contain additives such as anionic polyelectrolytes and anionic polyelectrolytes are more commercially adopted by semiconductor chip-makers [9][10][11] than amino acid additives [8,12].…”

Section: Introductionmentioning

confidence: 99%

“…The selectivity improvement achieved by using ceria-based slurry instead of silica-based slurry can be explained by two factors: the surface properties [7,8] and crystalline structure [9] of the ceria abrasive, and excess additive adsorption on the Si 3 N 4 layer [10][11][12]. However, the colloidal interactions between the abrasives, polished layer, and additives that occur during the use of ceria abrasives have not been studied extensively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Kim

Lee

et al. 2008

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Kim

Lee

et al. 2008

Journal of Colloid and Interface Science

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“…This strong hydrogen bonding on the nitride surface hinders the hydrolysis reaction, a rate limiting step in nitride removal mechanism, 7,22,23 by either impeding the reaction of water with the surface amines 22 or by blocking the surface amine protonation and subsequent water attack 23 and, hence, suppresses the nitride RRs. Therefore, both pyridine and acetic acid species with associated proton below pH 6 are able to bind to nitride surface amines through hydrogen bonding and hinder the hydrolysis reaction, there by suppressing the nitride RR.…”

Section: Ecs Journal Of Solid State Science Andmentioning

confidence: 99%

Further Investigation of Slurry Additives for Selective Polishing of SiO₂Films over Si₃N₄Using Ceria Dispersions

Penta

Amanapu

Babu

2015

ECS J. Solid State Sci. Technol.

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Following our earlier analysis of amino acids, we investigated the effectiveness of acetic acid, pyridine, and sorbitol that were chosen to represent carboxylic acid, amine and alcohol functional group families, respectively, as additives in ceria dispersions for polishing SiO 2 and Si 3 N 4 films. By comparing the speciation of the additives available and the material removal rates with respect to pH, we identified that the removal rates of nitride, but not oxide, are suppressed to <1 nm/min in the pH range where the additive species containing a protonated amino group or a neutral carboxylic group or a neutral hydroxyl group are dominant. All of these species are strong hydrogen bond donors and can form strong hydrogen bonds with Si 3 N 4 surface while their corresponding bonding on SiO 2 surface sites is weaker. The stronger hydrogen bonding hinders Si 3 N 4 hydrolysis and suppresses Si 3 N 4 removal. In contrast, the weakly bound additive species are easily removed from the SiO 2 surface by the polishing pad and the ceria abrasives, leading to high SiO 2 to Si 3 N 4 removal rate selectivity. Similar results were also obtained with valeric acid, imidazole, glucose, sucrose, and mannitol, confirming the importance of a strong hydrogen bond formation in a broader class of additives. Shallow trench isolation (STI), which helps isolate the transistors and prevents shorting and cross-talk, is a widely used process in semiconductor device fabrication. The STI process includes the deposition of silicon nitride on a thermally grown pad oxide followed by the etching of a shallow trench into the silicon substrate. A layer of silicon oxide such as tetraethyl ortho silicate (TEOS) oxide, high density plasma (HDP) oxide, or high aspect ratio process (HARP) oxide is deposited on the entire substrate surface, not only filling the trenches but also creating an uneven topography. After the trenches are filled, the excess deposited oxide needs to be removed and the topography planarized before the fabrication of any IC elements. So far, chemical mechanical polishing/planarization (CMP) has been the only viable technique to remove the overburden oxide and planarize the topographies. This STI CMP step requires a slurry which polishes the overburden oxide with high oxide removal rate (RR) and stops on the underlying nitride surface with minimal nitride loss and oxide dishing.Ceria-based dispersions 1 containing various additives have a huge market position for planarizing these STI structures efficiently because of their superior ability to polish oxide films at high rates using only a low solids loading of ∼1 wt% or less and to stop on the underlying nitride film with minimal loss as well as dishing. 2,3 In the absence of any additive, these same ceria slurries would also produce significant nitride RRs and lead to considerable nitride loss. Hence, many types of additives (amino acids, amines, surfactants, polymers and acids) were investigated to achieve high oxide-to-nitride rate selectivity. 4-12For example, America and Babu ...

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“…After these processes, the step height of gap-filling materials is inevitably formed due to the different pattern density, which needs to be removed. Chemical mechanical planarization (CMP) process removes the step height of the gap-filling materials [4,5], and it is stopped on the Si 3 N 4 film [6,7]. Contrary to these former STI CMP processes, current processes require an over-polishing step to completely remove SiO 2 on Si 3 N 4 film because the number of maximum permissible defects has been decreased with recent developments in 40 nm node devices and beyond.…”

Section: Introductionmentioning

confidence: 99%

Interpolymer complexes of poly(acrylic acid) and poly(ethylene glycol) for low dishing in STI CMP

Seo

Moon

et al. 2015

Applied Surface Science

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Interfacial Reactivity Between Ceria and Silicon Dioxide and Silicon Nitride Surfaces

Cited by 53 publications

References 11 publications

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Further Investigation of Slurry Additives for Selective Polishing of SiO₂Films over Si₃N₄Using Ceria Dispersions

Interpolymer complexes of poly(acrylic acid) and poly(ethylene glycol) for low dishing in STI CMP

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Interfacial Reactivity Between Ceria and Silicon Dioxide and Silicon Nitride Surfaces

Cited by 53 publications

References 11 publications

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Adsorption behavior of anionic polyelectrolyte for chemical mechanical polishing (CMP)

Further Investigation of Slurry Additives for Selective Polishing of SiO2Films over Si3N4Using Ceria Dispersions

Interpolymer complexes of poly(acrylic acid) and poly(ethylene glycol) for low dishing in STI CMP

Contact Info

Product

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Further Investigation of Slurry Additives for Selective Polishing of SiO₂Films over Si₃N₄Using Ceria Dispersions