The effect of hydrogen peroxide in chemical mechanical planarization slurries for shallow trench isolation was investigated. The various abrasives used in this study were ceria, silica, alumina, zirconia, titania, silicon carbide, and silicon nitride. Hydrogen peroxide suppresses the polishing of silicon dioxide and silicon nitride surfaces by ceria abrasives. The polishing performances of other abrasives were either unaffected or enhanced slightly with the addition of hydrogen peroxide. The ceria abrasives were treated with hydrogen peroxide, and the polishing of the work surfaces with the treated abrasive shows that the inhibiting action of hydrogen peroxide is reversible. It was found that the effect of hydrogen peroxide as an additive is a strong function of the nature of the abrasive particle. © 2008 Elsevier B.V. All rights reserved.

Srinivasan Ramanathan

Department Of Chemical Engineering

Additives

Alumina

Aluminum oxide

Catalyst selectivity

Cerium oxide

CHEMICAL MECHANICAL POLISHING

Hydrogen peroxide

Nitrides

oxidation

Peroxides

Polishing

silica

Silicon carbide

Silicon nitride

Titanium dioxide

Zirconia

Abrasive particles

Effect of hydrogen

NITRIDE SURFACE

REMOVAL RATE

SHALLOW TRENCH ISOLATION

Titania

Abrasives

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Applied Surface Science

Amino acids, when used with ceria based slurries, yield high selectivity in shallow trench isolation chemical mechanical polishing (CMP). However, the presence of impurities in the abrasives also plays a role in determining the selectivity. Experiments were performed with two different ceria abrasives, one with high purity and the other with controlled lanthanum doping. Various amino acids were evaluated in order to identify the nature of interaction between the additives and the abrasives. The abrasives were further characterized using transmission electron microscopy, X-ray diffraction and X-ray photo-electron spectroscopy. The removal rate results show that glycine and proline are sensitive to the La doping in the ceria abrasive whereas the other amino acids studied suppress the nitride removal irrespective of the purity of the abrasives. Thermo-gravimetric analysis shows that the extent of adsorption of glycine or proline on ceria depends on the presence of La doping, whereas the other amino acids adsorb equally well on ceria abrasives with or without La doping. © 2015 Elsevier Ltd. All rights reserved.

Materials Science in Semiconductor Processing

Effect of lanthanum doping in ceria abrasives on chemical mechanical polishing selectivity for shallow trench isolation

Electrical isolation of the billion or so active components in each integrated device is achieved using shallow trench isolation (STI) which requires chemical mechanical planarization (CMP) involving silicon dioxide removal at a high rate and stopping on an underlying silicon nitride film. Several colloidal slurries with various additives can yield the desired high rate selectivity between the oxide and nitride films during CMP while maintaining an acceptably low nitride rate. Here, many of such high selectivity STI CMP slurries described in the literature are reviewed along with the characteristics of the colloidal dispersions like the abrasives, additives, the interactions between them and with the films being planarized and the associated pH range in which the high selectivity is observed. The mechanisms proposed to explain the high reactivity of ceria with oxide, the role of additives in suppressing the nitride removal rate and resulting high selectivity are discussed. Reduction of a multitude of defects in post-CMP processed STI structures still remains an important challenge, especially as the feature sizes continue to shrink. © The Author(s) 2015. Published by ECS.

ECS Journal of Solid State Science and Technology

Shallow trench isolation chemical mechanical planarization: A review

Ceria based slurries with additives are widely used in shallow trench isolation (STI) chemical mechanical planarization (CMP) process to obtain high selective removal of silicon dioxide over silicon nitride. In this study ceria from different sources were used as abrasives and l-proline and l-glutamic acid were used as additives, with a focus on identifying the interactions between abrasives and additives and their effect of selectivity. Ceria particles were characterized using X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) while the additive abrasive interactions were evaluated by UV-Visible spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. While slurries with l-proline yielded high selectivity only with certain type of ceria, slurries with l-glutamic acid were found to be less sensitive to the ceria source than those with l-proline, and yielded high selectivity regardless of the source of ceria used. The purity of the abrasive and its crystal structure appear to play a significant role in determining the selectivity. © 2013 Elsevier B.V. All rights reserved.

Microelectronic Engineering

Abrasive and additive interactions in high selectivity STI CMP slurries

dl-aspartic acid as a removal rate selectivity enhancer for shallow trench isolation chemical mechanical polishing slurries was investigated over a pH range. The effects of downward pressure, rotational speed of the turntable as well as the ceria abrasive loading were also examined. The selectivity is very sensitive to changes in the pressure but not to changes in the rotational speed. Select experiments were also conducted with other types of abrasives with and without the additive. A comparison of the pKa values of the amino acid with the variation of the selectivity with pH indicates that the form of amino acid plays a vital role in determining the polishing behavior and the selectivity. Further, the results corroborate the hypothesis that chemically active sites on the abrasive may be blocked by certain forms of the amino acids, leading to changes in the selectivity. © 2010 Elsevier B.V. All rights reserved.

Thin Solid Films

Mechanism of high selectivity in ceria based shallow trench isolation chemical mechanical polishing slurries

Selectivity (oxide/nitride polish rate) is a critical factor during chemical mechanical polishing (CMP) of shallow trench isolation (STI) structure, and it can be modified by adding amino acids to the slurry. The role of adsorption of the amino acids L-proline and L-arginine, on silicon dioxide and silicon nitride surfaces was characterized as a function of pH and concentration using thermogravimetric analysis. The results suggest that the adsorption behavior does not correlate with the polishing behavior of STI CMP and hence it may not play a key role in changing the selectivity. © 2006 The Electrochemical Society.

Fulltext

Electrochemical and Solid-State Letters

Role of amino-acid adsorption on silica and silicon nitride surfaces during STI CMP

MRS Proceedings

Ceria concentration effect on chemical mechanical polishing of optical glass

Journal of Molecular Structure

A study of interaction between hydrogen peroxide and silica gel by FTIR spectroscopy and quantum chemistry

Journal of The Electrochemical Society

A Tribochemical Study of Ceria-Silica Interactions for CMP

The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

Journal	Data powered by TypesetApplied Surface Science
Publisher	Data powered by TypesetElsevier
ISSN	01694332
Open Access	No