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Cobalt (Co) has been identified as the promising candidate material due to the technology node goes down to 7nm and below. In this paper, the effect of diethylenetriamine pentaacetate pentapotassium (DTPA) on chemical mechanical polishing (CMP) of cobalt (Co) in H2O2 based slurry at pH 9 was studied. The roles of DTPA on the Co material removal process are discussed and a removal mechanism is proposed. The studied result shown that the removal rate (RR) was significantly improved by added DTPA, due to the Co and DTPA reaction Co-DTPA complex. The test results of electrochemical, UV-Vis and XPS also shows the DTPA has obvious chelation for Co.

When the technology node goes down to 7nm and below, cobalt (Co) has been identified as the promising candidate for the inter-connect/contact material. In this paper, we investigated the effect of amine based chelating agent and H2O2 on cobalt contact chemical mechanical polishing (CMP) in colloidal silica based slurry at pH 8. It revealed that the combination of H2O2 and FA/O II can significantly improve the cobalt removal rate (RR) by an order of magnitude. The electrochemical measurements, X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy experiments were applied to explore the removal machanism of Co film. The high removal rate of Co may be due to the formation of the water-soluble Co(III)-FA/O II complex. And relatively low dissolution ([?]1 nm/min) and good surface quality was achieved by adding a novel corrosion inhibitor.

Co/TaN has been considered as one of the most promising candidates for barrier layers with the feature size of integrated circuit (IC) shrinking to 14 nm and below. The present work investigates the effect of chelating agent and non-ionic surfactant on Co/Cu/TaN CMP in weakly alkaline slurry without any oxidizer. The results show that TaN removal rate increases to the peak value 526 A/min as the chelator concentration is 1ml/L. That is due to the formation of the water-soluble complex on the surface of TaN. What's more, the TaN removal rate reaches to 501 A/min and the root mean square roughness (Sq) of TaN is 0.654 nm when non-ionic surfactant concentration is 10 ml/L under the system of 1 ml/L of the chelator. Meanwhile, by the cross-over experiment, it is when slurry is composed of 5 wt% abrasive content, 1 ml/L chelator and 10 ml/L non-ionic surfactant at pH 10 that removal selectivity of Co:Cu and TaN:Cu are comparatively higher and closer (Co:Cu[?]2.74:1, TaN:Cu[?]2.61:1) along with a good surface quality is obtained.

The chemical mechanical polishing (CMP) of ruthenium (Ru) based barrier layer has been a key process in the manufacture of a novel copper (Cu) interconnect structure. The removal rate selectivity of Ru to Cu play a major role during Ru CMP as the technology scaling down to 14 nm. In this paper, the removal rate selectivity of Ru to Cu was studied by using guanidine carbonate (GC) as complexing agent and 1, 2, 4-triazole (TAZ) as inhibitor in hydrogen peroxide (H2O2) based slurry. The study results show that the removal rate selectivity of Ru to Cu can be controlled by adjusting the GC and TAZ contents, and the dishing and erosion of Cu patterned wafers can be corrected under the conditions with high removal rate selectivity of Ru to Cu. The influence mechanism of GC and TAZ on removal rates of Cu and Ru was investigated by electrochemistry, scanning electron microscope and X-Ray photoelectron spectroscopy. It is revealed that the soluble Cu-Guanidine (Cu-Gnd) and Ru-Guanidine (Ru-Gnd) complexes would be generated through the chemical reaction between Cu, Ru, and the complexes, which improves the removal rate of Cu and Ru. While TAZ can effectively reduce the Cu removal rate by protecting the Cu surface from corrosion. Furthermore, high removal selectivity and low surface roughness of Cu and Ru can be achieved simultaneously under the effect of GC and TAZ.

Object In recent years, transcranial MR-guided focused ultrasound (tcMRgFUS) has been established as a potential treatment option for movement disorders, including essential tremor. So far, however, little is known about the impact of tcMRgFUS on structural connectivity. The objective of this study was to detect microstructural changes in tremor- and motor-related white matter tracts in essential tremor patients treated with tcMRgFUS thalamotomy. Methods Eleven patients diagnosed with essential tremor were enrolled in this tcMRgFUS thalamotomy study. For each patient, 3T MRI including structural and diffusion MRI were acquired and the Clinical Rating Scale for Tremor was assessed prior to the procedure as well as one year after the treatment. Diffusion MRI tractography was performed to identify the cerebello-thalamo-cortical tract (CTCT), the medial lemniscus (ML) and the corticospinal tract (CST) in both hemispheres on pre-treatment data. Pre-treatment tractography results were co-registered to post-treatment diffusion data. Diffusion tensor imaging (DTI) metrics, including fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD), were averaged across the tracts in the pre- and post-treatment data. Results The mean value of tract-specific DTI metrics changed significantly within the thalamic lesion and in the CTCT on the treated side (p<0.05). Changes of DTI-derived indices within the CTCT correlated well with lesion overlap (FA: r=-0.54, p=0.04; MD: r=0.57, p=0.04); RD: r=0.67, p=0.036). Furthermore, a trend was seen for the correlation between changes of DTI-derived indices within the CTCT and clinical improvement (FA: r=0.58; p=0.062; MD: r=-0.52, p=0.64; RD: r=-0.61 p=0.090). Conclusions Microstructural changes were detected within the CTCT after tcMRgFUS and these changes correlated well with lesion-tract overlap. Our results show that diffusion MRI is able to detect the microstructural effects of tcMRgFUS, thereby further elucidating the treatment mechanism and ultimately to improve targeting prospectively.

Cobalt (Co) has been identified as the promising candidate material due to the technology node goes down to 7nm and below. In this paper, the effect of diethylenetriamine pentaacetate pentapotassium (DTPA) on chemical mechanical polishing (CMP) of cobalt (Co) in H2O2based slurry at pH 9 was studied. The roles of DTPA on the Co material removal process are discussed and a removal mechanism is proposed. The studied result shown that the removal rate (RR) was significantly improved by added DTPA, due to the Co and DTPA reaction Co-DTPA complex. The test results of electrochemical, UV-Vis and XPS also shows the DTPA has obvious chelation for Co.

Co/TaN has been considered as one of the most promising candidates for barrier layers with the feature size of integrated circuit (IC) shrinking to 14 nm and below. The present work investigates the effect of chelating agent and non-ionic surfactant on Co/Cu/TaN CMP in weakly alkaline slurry without any oxidizer. The results show that TaN removal rate increases to the peak value 526 Å/min as the chelator concentration is 1ml/L. That is due to the formation of the water-soluble complex on the surface of TaN. What's more, the TaN removal rate reaches to 501 Å/min and the root mean square roughness (Sq) of TaN is 0.654 nm when non-ionic surfactant concentration is 10 ml/L under the system of 1 ml/L of the chelator. Meanwhile, by the cross-over experiment, it is when slurry is composed of 5 wt% abrasive content, 1 ml/L chelator and 10 ml/L non-ionic surfactant at pH 10 that removal selectivity of Co:Cu and TaN:Cu are comparatively higher and closer (Co:Cu∼2.74:1, TaN:Cu∼2.61:1) along with a good surface quality is obtained.

The chemical mechanical polishing (CMP) of ruthenium (Ru) based barrier layer has been a key process in the manufacture of a novel copper (Cu) interconnect structure. The removal rate selectivity of Ru to Cu play a major role during Ru CMP as the technology scaling down to 14 nm. In this paper, the removal rate selectivity of Ru to Cu was studied by using guanidine carbonate (GC) as complexing agent and 1, 2, 4-triazole (TAZ) as inhibitor in hydrogen peroxide (H2O2) based slurry. The study results show that the removal rate selectivity of Ru to Cu can be controlled by adjusting the GC and TAZ contents, and the dishing and erosion of Cu patterned wafers can be corrected under the conditions with high removal rate selectivity of Ru to Cu. The influence mechanism of GC and TAZ on removal rates of Cu and Ru was investigated by electrochemistry, scanning electron microscope and X-Ray photoelectron spectroscopy. It is revealed that the soluble Cu-Guanidine (Cu-Gnd) and Ru-Guanidine (Ru-Gnd) complexes would be generated through the chemical reaction between Cu, Ru, and the complexes, which improves the removal rate of Cu and Ru. While TAZ can effectively reduce the Cu removal rate by protecting the Cu surface from corrosion. Furthermore, high removal selectivity and low surface roughness of Cu and Ru can be achieved simultaneously under the effect of GC and TAZ.

When the technology node goes down to 7nm and below, cobalt (Co) has been identified as the promising candidate for the inter-connect/contact material. In this paper, we investigated the effect of amine based chelating agent and H2O2on cobalt contact chemical mechanical polishing (CMP) in colloidal silica based slurry at pH 8. It revealed that the combination of H2O2and FA/O II can significantly improve the cobalt removal rate (RR) by an order of magnitude. The electrochemical measurements, X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy experiments were applied to explore the removal machanism of Co film. The high removal rate of Co may be due to the formation of the water-soluble Co(III)-FA/O II complex. And relatively low dissolution (≤1 nm/min) and good surface quality was achieved by adding a novel corrosion inhibitor.