Development of an etchant for selectively etching TiWNxin the presence of electroplated 95%Pb-5%Sn solder

Shrinking die sizes and increasing I/O density is motivating the push toward flip chip packages. A flip chip interconnection system with a under bump metallurgy stack containing sputtered TiWN_X/sputtered Cu/electroplated Cu stud/electroplated 95%Pb-5%Sn was developed. An important step in the above process is the selective etching of the sputtered Cu bus layer and the TiWN_X barrier layer, in the presence of the Pb-Sn solder. The Cu bus layer was selectively etched using commercial etchants. However, no commercial etchants were available for selectively etching the TiWN_X layer, H₂O₂-NH₄OH based etching systems, popularly known as Standard Clean-1 cleaning solutions, have been extensively used to clean silicon wafers in front end wafer fabrication where only trace metal contamination exists. Since metals like lead, copper, titanium, tin and tungsten catalyze the heterogeneous decomposition of the peroxide, the unstable H₂O₂-NH₄OH based etching systems are rarely used to etch metal films. In this paper the development of a H ₂O₂-NH₄OH based etchant to selectively etch the sputtered TiWN_X films in the presence of electroplated 95%Pb-5%Sn solder bumps is discussed. A 2³ full factorial experiment with mid point was conducted to establish the etchant composition, as well as process temperature, that give satisfactory responses with respect to etch time, permissable undercut of the Cu stud (caused by the NH₄OH), and acceptable bump shape after reflow. Statistical analysis was used to understand the significant factors influencing the etch rate and undercut. An etchant containing 6% by volume of 30%-H₂O₂ and 0.75% by volume of 30%-NH₄OH operated at a temperature of 37°C was found to give satisfactory results     

Magnetoresistance,magnetothermopower, magnetothermal conductivity and magnetostriction in La1-xNaxMnO3 (0≤x≤0.05)

We report the influence of the magnetic field on electrical resistivity (ρ), thermal conductivity (κ), thermopower (S), and linear thermal expansion (ΔL/L₀) in La_1-xNa_xMnO₃ series (x = 0, 0.01, 0.02, and 0.05) over a wide range of temperature. While LaMnO₃ is an antiferromagnetic insulator, the doping with Na weakens the inter-planner antiferromagnetic coupling and transforms it into a ferromagnetic metal by promoting the double exchange coupling between Mn³⁺ and Mn⁴⁺ ions. ρ and S show peaks, whereas, κ shows a sudden increase at the onset of ferromagnetic spin ordering in the samples. Dominant charge carriers are holes in these doped compounds as indicated by the positive sign of S. High-temperature transport is explained in the context of the small polaron hopping model. External magnetic field influences thermal properties (S and κ), and ΔL/L₀ mostly around the Curie temperature (T_C), while it affects ρ to as low as 10 K. Enhancement of κ at the insulator-metal transition, on the application of external magnetic field, suggests a decrease in spin-wave scattering. The highest value of negative magnetoresistance (~69.7%) and negative magnetothermopower (~80.4%) is obtained for x = 0.02 and the value decreases for higher dopant concentration.     

A generic iconic tool for viewing databases

Many software-development environments capture and structure all project information in one or more databases. As these data-gathering techniques become more effective, they make it increasingly difficult to locate relevant information from a vast store. Adapt is a display tool that can depict both the structure and content of databases graphically. The architecture of Adapt and the augmented graph representation it uses for database objects are described. As an example, the use of Adapt with the Triad database, which has 400 objects of 24 types, ranging from management (personnel information, project objectives, reviews, and walkthroughs) to coding (components and modules), is considered. Two kinds of graph operation, display and adaptive, that an Adapt user can perform on the augmented graph are discussed.<>     

Conservation and deferral potentials of demand side management programmes: A case study

Demand side management options (DSMO) can reduce the peak electricity demand for utilities. This reduction in demand is helpful to the utility in at least two ways: first, it minimizes the penalty costs of not being able to meet the peak demand and thus it has the potential to reduce costs; second, it also can defer the need for building new power plants and hence it can release, at least for some period of time, the scarce capital (which is especially important for the developing countries) for use in development activities elsewhere. These two benefits have been considered in detail in the paper. An analytical model has been developed to estimate the conservation potential of the DSM programmes. The model is then used to illustrate the benefit derived by deferring the construction of a new power plant. The model has been applied to the Maharashtra State Electricity Board, an electric utility in India, as a case study. Several scenarios have been constructed to account for different levels of the DSM possibilites. A sensitivity analysis has been carried out to tackle some of the uncertainties associated with the assumptions in the analysis.     

Chemotherapy for advanced non-small cell lung cancer: past, present, and future

Until recently, chemotherapeutic intervention in advanced and metastatic non-small cell lung cancer (NSCLC) has been viewed with a certain degree of nihilism. Although meta-analysis of randomized clinical studies from the 1970s and 1980s comparing cisplatin-based chemotherapy to best supportive care in metastatic NSCLC showed improvement in survival, it was modest at best. A number of novel agents have been developed with significant activity against NSCLC in the past 5 to 6 years and are being incorporated into the therapy of this disease. These agents include paclitaxel, docetaxel, vinorelbine, gemcitabine, and irinotecan. Clearly there has been improvement in response rates, and in some cases the responses have been durable with an increase in the number of 1- and 2-year survivors. The next generation of studies has evaluated combinations of these novel agents with either cisplatin or carboplatin for patients with NSCLC and the results have been provocative, with 1-year survival rates as high as 54%. A randomized phase III study of the Eastern Cooperative Oncology Group has shown the superiority of paclitaxel-cisplatin regimens over etoposide-cisplatin for patients with advanced and metastatic NSCLC. The vinorelbine-cisplatin regimen has also proven to have significant, albeit modest benefit in survival when compared with cisplatin alone. These combination regimens have now become the reference regimens in ongoing randomized studies. There is continued interest in developing new agents, or selective approaches that effect novel targets with the hope of showing improved therapeutic activity. Some of these approaches include gene therapy, monoclonal antibodies, and introduction of antisense oligodeoxynucleotides. With better understanding of the molecular and cellular biology of lung cancer, the hope for the future is to combine the mechanistic approaches with new drug development to define an effective, optimal, and definitive regimen for NSCLC.     

Network-Level QoS Assurances Through Adaptive Allocation of CDMA Resources

In a Code Division Multiple Access (CDMA) network, multiple Mobile Hosts (MHs) can simultaneously transmit over the wireless channel by using different codes. To assure an acceptable Quality of Service (QoS) for all MHs' flows, the network usually tunes the transmit powers of all MHs to achieve a certain level of signal strength as compared to the noise and the interference (SINR) for each MH. The traditional assumption in power control schemes is that the SINR requirement is statically determined for each MH's flow. In contrast, in this paper, we propose a scheme that dynamically adapts the SINR requirements of MH's flow based on its QoS requirements and the conditions of the wireless channel between the MHs and the base station. As a result of this adaptation, we show that network-level QoS measures such as fraction of packets meeting their delay requirements and energy consumed per packet transmission are significantly better than in a scheme that statically fixes the SINR requirements. We show that the adaptation approach works well for the Matched Filter (MF) and the Minimum Mean Squared Error (MMSE) receivers. Our scheme uses a simple table-driven approach for optimally selecting the target SINR requirement for each MH at run time. The entries in the table are computed off-line using a dynamic programming algorithm with the objective of maximizing a profit function that balances the need for meeting the network-level QoS requirements and the cost of using a particular target SINR for a given transmission. Moncef Elaoud (M'97) received his B.Sc. (1988) his M.Sc. (1990) and his Ph.D. (2000) in electrical an computer engineering from the University of Wisconsin-Madison. He is currently a senior research Scientist at Telcordia Technologies' Applied Research organization. His main research interests are in the areas of quality of service, self-forming and self healing networks, auto-configuration, and mobility management in wireless and ad-hoc networks. Bechir Hamdaoui received the B.S. degrees in both electrical and mechanical engineering, and the M.S. degree in mechanical engineering from the National School of Engineering in Tunis (BAC+6+DEA, ENIT), Tunisia, in 1997 and 1998, respectively. He also received the M.S. degree in electrical and computer engineering from the University of Wiconsin, Madison, WI, in 2002, where he is currently working toward the Ph.D. degree. From 1998 to 1999, he worked as a quality control and planning engineer on power generation plant project under the supervision of FIAT Avio. His research focuses on various aspects in the area of computer networking including mobile networks, wireless communication systems, and ad hoc networks. Parameswaran Ramanathan received the B. Tech degree from the Indian Institute of Technology, Bombay, India, in 1984, and the M. S. E. and Ph. D. degrees from the University of Michigan, Ann Arbor, in 1986 and 1989, respectively. Since 1989, Dr. Ramanathan has been faculty member in the Department of Electrical & Computer Engineering, University of Wisconsin, Madison, where is presently a Full Professor. He leads research projects in the areas of sensor networks and next generation cellular technology. In 1997–98, he took a sabbatical leave to visit research groups at AT&T Laboratories and Telcordia Technologies. Dr. Ramanathan's research interests include wireless and wireline networking, real-time systems, fault-tolerant computing, and distributed systems. He is presently an Associate Editor for IEEE Transactions on Mobile Computing and Elsevier AdHoc Networks Journal. He served as an Associate Editor for IEEE Transactions on Parallel and Distributed Computing from 1996–1999. He has also served on program committees of conferences such as Mobicom, Mobihoc, International Conferences on Distributed Systems and Networks, Distributed Computing Systems, Fault-tolerant Computing Symposium, Real-time Systems Symposium, Conference on Local Computer Networks, and International Conference on Engineering Complex Computer Systems. He was the Finance and Registration Chair for the 1999 Fault-tolerant Computing Symposium. He was the program chairman of the Workshop on Architectures for Real-time Applications, 1994 and the program vice-chair for the International Workshop on Parallel and Distributed Real-time Systems, 1996. He is a member of Association of Computing Machinery and a senior member of IEEE.     

Adaptive power and rate allocation for service curve assurance in DS-CDMA network

This paper describes schemes for forward and reverse links in a direct sequence code-division multiple-access-based cellular network. The primary objective is to meet the diverse quality-of-service (QoS) needs of mobile hosts (MHs), and the secondary objective is to maximize the system throughput. The QoS needs of the MHs are modeled using the notion of a service curve. Furthermore, a notion of deviation is introduced as a measure of meeting service curve. The scheme proposed in this paper jointly adapts the transmitted power and the number of spreading codes assigned to each MH for receiving/transmitting its data bits. The scheme imposes practical constraints including bounds on the transmitted power for a base station and MHs, a bound on the number of spreading codes that an MH can handle, and minimum signal-to-interference-plus-noise ratio at the receiver. The proposed solutions are evaluated using discrete event simulations. The simulation results characterize the performance of the proposed solutions for several instances of the practical constraints.     

Future directions for resuscitation research. III. External cardiopulmonary resuscitation advanced life support

This discussion about advanced cardiac life support (ACLS) reflects disappointment with the over 50% of out-of-hospital cardiopulmonary resuscitation (CPR) attempts that fail to achieve restoration of spontaneous circulation (ROSC). Hospital discharge rates are equally poor for in-hospital CPR attempts outside special care units. Early bystander CPR and early defibrillation (manual, semi-automatic or automatic) are the most effective methods for achieving ROSC from ventricular fibrillation (VF). Automated external defibrillation (AED), which is effective in the hands of first responders in the out-of-hospital setting, should also be used and evaluated in hospitals, inside and outside of special care units. The first countershock is most important. Biphasic waveforms seem to have advantages over monophasic ones. Tracheal intubation has obvious efficacy when the airway is threatened. Scientific documentation of specific types, doses, and timing of drug treatments (epinephrine, bicarbonate, lidocaine, bretylium) are weak. Clinical trials have failed so far to document anything statistically but a breakthrough effect. Interactions between catecholamines and buffers need further exploration. A major cause of unsuccessful attempts at ROSC is the underlying disease, which present ACLS guidelines do not consider adequately. Early thrombolysis and early coronary revascularization procedures should also be considered for selected victims of sudden cardiac death. Emergency cardiopulmonary bypass (CPB) could be a breakthrough measure, but cannot be initiated rapidly enough in the field due to technical limitations. Open-chest CPR by ambulance physicians deserves further trials. In searches for causes of VF, neurocardiology gives clues for new directions. Fibrillation and defibrillation thresholds are influenced by the peripheral sympathetic and parasympathetic nervous systems and impulses from the frontal cerebral cortex. CPR for cardiac arrest of the mother in advanced pregnancy requires modifications and outcome data. Until more recognizable critical factors for ROSC are identified, titrated sequencing of ACLS measures, based on physiologic rationale and sound judgement, rather than rigid standards, gives the best chance for achieving survival with good cerebral function.     

Joint Estimation of Human Pose and Conversational Groups from Social Scenes

Despite many attempts in the last few years, automatic analysis of social scenes captured by wide-angle camera networks remains a very challenging task due to the low resolution of targets, background clutter and frequent and persistent occlusions. In this paper, we present a novel framework for jointly estimating (i) head, body orientations of targets and (ii) conversational groups called F-formations from social scenes. In contrast to prior works that have (a) exploited the limited range of head and body orientations to jointly learn both, or (b) employed the mutual head (but not body) pose of interactors for deducing F-formations, we propose a weakly-supervised learning algorithm for joint inference. Our algorithm employs body pose as the primary cue for F-formation estimation, and an alternating optimization strategy is proposed to iteratively refine F-formation and pose estimates. We demonstrate the increased efficacy of joint inference over the state-of-the-art via extensive experiments on three social datasets.     

Fabrication of chitosan microparticles loaded in chitosan and poly(vinyl alcohol) scaffolds for tissue engineering application

In recent decades, the use of microparticle-mediated drug delivery is widely applied in the field of biomedical application. Here, we report the new dressing material with ciprofloxacin-loaded chitosan microparticle (CMP) impregnated in chitosan (CH) and poly(vinyl alcohol) (PVA) scaffold for effective delivery of drug in a sustained manner to the wound site. Moreover, the peculiar physiochemical and structural properties of the CH–CMP scaffold has proved better tensile strength and excellent swelling to achieve 82% of drug release. In vitro biocompatibility was done for both scaffold using NIH 3T3 fibroblasts and human keratinocytes (HaCaT) cell lines. In vitro fluorescent activity showed distinct biocompatibility with good cell adhesion and proliferation. However, the CH–CMP scaffold showed best result to act as promising biomaterial in effective drug delivery in tissue engineering.