Charaterization of 5-aminotetrazole (ATRA) as a corrosion inhibitor in copper chemical mechanical polishing

In the Cu metallization process, it is important to prevent corrosion and recession of metal lines resulting from chemical reactions during the chemical mechanical polishing CMP process. In this paper, 5-aminotetrazole ATRA is investigated as a corrosion inhibitor for Cu CMP. In the wet etch test, it was found that the etch rate of ATRA decreased with concentration. The potentiodynamic polarization test and chronoamperometry test results revealed that ATRA could inhibit the Cu surface against corrosion more effectively than benzotriazole BTA below 0.01 M. Fourier transform infrared and ultraviolet-visible analysis clearly demonstrated that ATRA dissociated more easily in all pH ranges and could be polymerized faster and more effectively than BTA. Therefore, both corrosion and recession could be considerably reduced after CMP by using slurry containing ATRA. Furthermore, from the results of defect review after CMP, it was found that defects such as slurry residue, pit corrosion, and particles were effectively prevented due to small molecular size and high solubility of ATRA

A STUDY ON THE LONG-TERM MONITORING OF SPORTS ACTIVITIES

INTRODUCTION: Lots of studies to analyze and classify human movement patterns using various sensors have been carried out (Mathie, 2004; Allen, 2006) because accurate information of body activity is required to provide promotion of health and health plan. Thus this study was conducted to study the classification and monitoring of various sports activities in real-time environment using single waist mounted tri-axial accelerometer

Arrhythmia surgery for atrial fibrillation associated with atrial septal defect: Right-sided maze versus biatrial maze

BackgroundAlthough it has been inferred that a biatrial maze procedure for atrial fibrillation in left-sided heart lesions may lead to better outcomes compared with a limited left atrial lesion set, it remains controversial whether the biatrial maze procedure is superior to the right atrial maze procedure in right-sided heart lesions.MethodsA retrospective review was performed for 56 adults who underwent surgical closure of atrial septal defect and various maze procedures for atrial fibrillation between June 1998 and February 2011. The median age at operation was 59 years (range, 34-79 years). Clinical manifestations of atrial fibrillation were paroxysmal in 8 patients, persistent in 15 patients, and long-standing persistent in 33 patients. A right atrial maze procedure was performed in 23 patients (group 1), and a biatrial maze procedure was performed in 33 patients (group 2). Treatment failure was defined as atrial fibrillation recurrence, development of atrial flutter or other types of atrial tachyarrhythmia, or implantation of a permanent pacemaker. The Cox proportional hazards model was used to identify risk factors for decreased time to treatment failure.ResultsDuring the median follow-up period of 49 months (range, 5-149 months), there was no early death and 1 late noncardiac death. On Cox survival model, group 1 showed a significantly decreased time to treatment failure in comparison with group 2 (hazard ratio, 5.11; 95% confidence interval, 1.59-16.44; P = .006). Maintenance of normal sinus rhythm without any episode of atrial fibrillation recurrence at 2 and 5 years postoperatively was 57% and 45% in group 1, respectively, and 82% and 69% in group 2, respectively.ConclusionsLeft-sided ablation in addition to a right atrial maze procedure leads to better electrophysiologic outcome in atrial fibrillation associated with atrial septal defect

Effects of OH radicals on formation of Cu oxide and polishing performance in Cu Chemical Mechanical Polishing

The amount of OH radicals generated varied according to the complexing agent or Cu ion, and the accelerating effect of OH radicals on the rate of Cu oxide formation was found in acidic pH. When Cu I ions and oxalic acid were added to H2O2-based slurry, the decreases in etch and removal rates of Cu were observed because more generation of OH radicals resulted in the formation of thicker Cu oxide compared to additive-free slurry. Therefore, proper control of the formation and dissolution of Cu oxide led to an increase in etch and removal rates.This work was supported by the KOSEF through the Research Center for Energy Conversion and Storage (RCECS), Hanhwa Chemical, Ltd., and by the Institute of Chemical Processes (ICP) in Seoul National University