XPS and Electrochemical Studies on Tungsten-Oxidizer Interaction in Chemical Mechanical Polishing

1999 ◽  
Vol 566 ◽  
Author(s):  
Dnyanesh Tamboli ◽  
Sudipta Seal ◽  
Vimal Desai
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Electrochemical Measurements ◽  
Electrochemical Studies ◽  
Removal Mechanism ◽  
Tungsten Oxides ◽  
X Ray ◽  
Static Solutions

Electrochemical interaction between the oxidizer and the metal is believed to play a key role in material removal in tungsten CMP. In this study, we use X-ray Photoelectron Spectroscopy (XPS) in conjunction with electrochemical measurements in both in-situ polishing conditions as well as in static solutions, to identify the passivation and dissolution modes of tungsten. Dissolution of tungsten oxides was found to be the primary non-mechanical tungsten removal mechanism in CMP.

Effect of pH on ceria–silica interactions during chemical mechanical polishing

2005 ◽  
Vol 20 (5) ◽  
pp. 1139-1145 ◽  
Author(s):  
Jeremiah T. Abiade ◽  
Wonseop Choi ◽  
Rajiv K. Singh
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Mechanical Polishing ◽  
Mechanical Polishing ◽  
Force Measurements ◽  
X Ray ◽  
Force Microscopy ◽  
Substrate Interaction ◽  
Atomic Force ◽  
Silica Removal

To understand the ceria–silica chemical mechanical polishing (CMP) mechanisms, we studied the effect of ceria slurry pH on silica removal and surface morphology. Also, in situ friction force measurements were conducted. After polishing; atomic force microscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy were used to quantify the extent of the particle–substrate interaction during CMP. Our results indicate the silica removal by ceria slurries is strongly pH dependent, with the maximum occurring near the isoelectric point of the ceria slurry.

Effects of Metallic Impurities in Alkaline Electrolytes on Electro-Oxidation of Water and Alcohol Molecules

2021 ◽  
Author(s):  
Yi Shen ◽  
Yongfang Zhou ◽  
Hongying Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Measurements ◽  
Metallic Ions ◽  
Impurity Effects ◽  
X Ray ◽  
Fundamental Understanding ◽  
Alkaline Electrolytes ◽  
Electro Oxidation ◽  
Metallic Impurities

Abstract The presence of metallic impurities in the electrolyte greatly affects electrocatalytic performance. A systematic study on this topic can not only provide guidance for rigorous practices on electrochemical measurements, but also in-depth fundamental understanding on the mechanisms of the electrochemical reactions. Herein, nine types of metallic ions including Cu2+, Ni2+, Fe3+, Fe2+, Co2+, Mn2+, Zn2+, Ce3+ and Al3+ are intentionally introduced into the electrolytes with a controlled manner and their effects on electro-oxidation of water, 5-hydroxymethylfurfural (HMF) and glycerol are investigated in details. Among these metal ions, Co2+ has the most pronounced effects on H2O electro-oxidation while Cu2+ species displays superior activity toward HMF and glycerol electro-oxidation, but negligible effects on H2O electro-oxidation. Such a unique feature of Cu2+ can also be noted from electro-oxidation of other small molecules, such as ethylene glycol, ethanol and furfural. More importantly, the effects of metallic impurities are independent of the composition of the electrodes, only rely on the pH of the electrolytes. In-situ electrochemical Raman spectroscopy, control electrochemical experiments and X-ray photoelectron spectroscopy analyses reveal that the origin of impurity effects is attributed to the formation of hydroxides during the electrochemical measurements.

scholarly journals Synthesis and Reactivity of (N2P2)Ni Complexes Stabilized by a Novel Diphosphonite Pyridinophane Ligand

2021 ◽  
Author(s):  
Kei Fuchigami ◽  
Michael B. Watson ◽  
Giang N. Tran ◽  
Nigam P. Rath ◽  
Liviu M. Mirica
Keyword(s):  
Photoelectron Spectroscopy ◽  
Aryl Halide ◽  
Bond Formation ◽  
Cross Coupling ◽  
Electrochemical Studies ◽  
Redox Potentials ◽  
Efficient Catalyst ◽  
X Ray ◽  
Ni Species

A series of (N2P2)Ni<sup>II</sup> complexes (N2P2 = P,P’-ditertbutyl-2,11-diphosphonito[3.3](2,6)pyridinophane) stabilized by a modified tetradentate pyridinophane ligand containing two phosphonite groups were synthesized and characterized. Cyclic voltammetry (CV) studies revealed the accessibility of the Ni<sup>I</sup> oxidation state at moderate redox potentials for these Ni<sup>II</sup> complexes. <i>In situ</i> EPR, low-temperature UV-vis, and electrochemical studies were employed to detect the formation of Ni<sup>I</sup> species during the reduction of Ni<sup>II</sup> precursors. Furthermore, the [(N2P2)Ni<sup>I</sup>(CNtBu)](SbF<sub>6</sub>) complex was isolated upon reduction of the Ni<sup>II</sup> precursor with 1 equiv of CoCp<sub>2</sub>, and was characterized by EPR and X-ray photoelectron spectroscopy (XPS). Finally, the (N2P2)Ni<sup>II</sup>Br<sub>2</sub> complex acts as an efficient catalyst for the Kumada cross-coupling of an aryl halide with an aryl or alkyl Grignard, suggesting that the N2P2 ligand can support the various Ni species involved in the catalytic C-C bond formation reactivity.

scholarly journals Synthesis and Reactivity of (N2P2)Ni Complexes Stabilized by a Novel Diphosphonite Pyridinophane Ligand

2021 ◽  
Author(s):  
Kei Fuchigami ◽  
Michael B. Watson ◽  
Giang N. Tran ◽  
Nigam P. Rath ◽  
Liviu M. Mirica
Keyword(s):  
Photoelectron Spectroscopy ◽  
Aryl Halide ◽  
Bond Formation ◽  
Cross Coupling ◽  
Electrochemical Studies ◽  
Redox Potentials ◽  
Efficient Catalyst ◽  
X Ray ◽  
Ni Species

A series of (N2P2)Ni<sup>II</sup> complexes (N2P2 = P,P’-ditertbutyl-2,11-diphosphonito[3.3](2,6)pyridinophane) stabilized by a modified tetradentate pyridinophane ligand containing two phosphonite groups were synthesized and characterized. Cyclic voltammetry (CV) studies revealed the accessibility of the Ni<sup>I</sup> oxidation state at moderate redox potentials for these Ni<sup>II</sup> complexes. <i>In situ</i> EPR, low-temperature UV-vis, and electrochemical studies were employed to detect the formation of Ni<sup>I</sup> species during the reduction of Ni<sup>II</sup> precursors. Furthermore, the [(N2P2)Ni<sup>I</sup>(CNtBu)](SbF<sub>6</sub>) complex was isolated upon reduction of the Ni<sup>II</sup> precursor with 1 equiv of CoCp<sub>2</sub>, and was characterized by EPR and X-ray photoelectron spectroscopy (XPS). Finally, the (N2P2)Ni<sup>II</sup>Br<sub>2</sub> complex acts as an efficient catalyst for the Kumada cross-coupling of an aryl halide with an aryl or alkyl Grignard, suggesting that the N2P2 ligand can support the various Ni species involved in the catalytic C-C bond formation reactivity.

Modeling and Analyzing on Nonuniformity of Material Removal in Chemical Mechanical Polishing of Silicon Wafer

2004 ◽  
Vol 471-472 ◽  
pp. 26-31 ◽  
Author(s):  
Jian Xiu Su ◽  
Dong Ming Guo ◽  
Ren Ke Kang ◽  
Zhu Ji Jin ◽  
X.J. Li ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Mechanical Polishing ◽  
Wafer Surface ◽  
Removal Mechanism ◽  
Particle Movement ◽  
Material Removal Mechanism ◽  
The Relationship ◽  
Nonuniform Material

Chemical mechanical polishing (CMP) has already become a mainstream technology in global planarization of wafer, but the mechanism of nonuniform material removal has not been revealed. In this paper, the calculation of particle movement tracks on wafer surface was conducted by the motion relationship between the wafer and the polishing pad on a large-sized single head CMP machine. Based on the distribution of particle tracks on wafer surface, the model for the within-wafer-nonuniformity (WIWNU) of material removal was put forward. By the calculation and analysis, the relationship between the motion variables of the CMP machine and the WIWNU of material removal on wafer surface had been derived. This model can be used not only for predicting the WIWNU, but also for providing theoretical guide to the design of CMP equipment, selecting the motion variables of CMP and further understanding the material removal mechanism in wafer CMP.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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