The Experts below are selected from a list of 19995 Experts worldwide ranked by ideXlab platform
Alan C. West - One of the best experts on this subject based on the ideXlab platform.
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An investigation of phosphate based ECMP electrolyte performance on feature scale Planarization
Journal of Applied Electrochemistry, 2009Co-Authors: Kristin G. Shattuck, Alan C. WestAbstract:Conventional copper chemical mechanical Planarization (CMP) techniques are being pushed to their limits by increasing industrial standards caused by device miniaturization and the use of new materials. There is a need to investigate alternative methods of polishing to maintain and/or improve Planarization standards while operating at low downforce. In this study, electrochemical mechanical Planarization (ECMP) is considered as an alternative and/or an extension to current CMP processes. ECMP is unique due to the combination of an applied voltage to oxidize Cu and an abrasion from a polishing pad, which potentially allows the system to achieve high levels of Planarization through the use of an appropriately tailored electrolyte. An electrolyte containing 1.0 M potassium phosphate salt concentration with a pH value of 2 and a benzotriazole (BTA) concentration of 0.001 M was tested for its Planarization capability on patterned Cu structures using a custom built ECMP tool. Feature sizes of the Cu structures were varied from 1 to 6 μm. Similar Planarization results were achieved using three pad types. All experiments were performed at 0.5 V versus Ag/AgCl reference. The average step height reduction (SHR) was ~840 nm while the decrease in the average metal thickness removed (λ_avg) was on the order of ~430 nm. Because features were approximately 50% of the substrate area, the total average metal thickness removed was approximately half of the SHR for all three pad types.
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Characterization of phosphate electrolytes for use in Cu electrochemical mechanical Planarization
Electrochimica Acta, 2008Co-Authors: Kristin G. Shattuck, Paula Cojocaru, Alan C. WestAbstract:Abstract Electrochemical mechanical Planarization (ECMP) is a potential replacement or complement to conventional chemical mechanical Planarization (CMP) techniques. ECMP can operate at very low downforces ( −1 within an operating potential window from 0.5 to 1.0 V vs. Ag/AgCl reference electrode.
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Electrochemical Planarization of interconnect metallization
IBM Journal of Research and Development, 2005Co-Authors: Alan C. West, Hariklia Deligianni, Panayotis C. AndricacosAbstract:Studies of the electropolishing of copper are reviewed. Recent work intended to demonstrate the electrochemical Planarization of the overburden in electroplated copper interconnect metallization is emphasized. Furthermore, two common reaction mechanisms invoked to explain the mass-transfer limitation required to achieve electropolishing are outlined and discussed within the context of anodic leveling, which has been more recently called electrochemical Planarization. Finally, scaling arguments are used to demonstrate practical considerations for tool development and to speculate about uncertainties in anodic leveling theories.
Kristin G. Shattuck - One of the best experts on this subject based on the ideXlab platform.
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An investigation of phosphate based ECMP electrolyte performance on feature scale Planarization
Journal of Applied Electrochemistry, 2009Co-Authors: Kristin G. Shattuck, Alan C. WestAbstract:Conventional copper chemical mechanical Planarization (CMP) techniques are being pushed to their limits by increasing industrial standards caused by device miniaturization and the use of new materials. There is a need to investigate alternative methods of polishing to maintain and/or improve Planarization standards while operating at low downforce. In this study, electrochemical mechanical Planarization (ECMP) is considered as an alternative and/or an extension to current CMP processes. ECMP is unique due to the combination of an applied voltage to oxidize Cu and an abrasion from a polishing pad, which potentially allows the system to achieve high levels of Planarization through the use of an appropriately tailored electrolyte. An electrolyte containing 1.0 M potassium phosphate salt concentration with a pH value of 2 and a benzotriazole (BTA) concentration of 0.001 M was tested for its Planarization capability on patterned Cu structures using a custom built ECMP tool. Feature sizes of the Cu structures were varied from 1 to 6 μm. Similar Planarization results were achieved using three pad types. All experiments were performed at 0.5 V versus Ag/AgCl reference. The average step height reduction (SHR) was ~840 nm while the decrease in the average metal thickness removed (λ_avg) was on the order of ~430 nm. Because features were approximately 50% of the substrate area, the total average metal thickness removed was approximately half of the SHR for all three pad types.
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Characterization of phosphate electrolytes for use in Cu electrochemical mechanical Planarization
Electrochimica Acta, 2008Co-Authors: Kristin G. Shattuck, Paula Cojocaru, Alan C. WestAbstract:Abstract Electrochemical mechanical Planarization (ECMP) is a potential replacement or complement to conventional chemical mechanical Planarization (CMP) techniques. ECMP can operate at very low downforces ( −1 within an operating potential window from 0.5 to 1.0 V vs. Ag/AgCl reference electrode.
Jianer Chen - One of the best experts on this subject based on the ideXlab platform.
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On the Planarization of Wireless Sensor Networks
Algorithmica, 2010Co-Authors: Fenghui Zhang, Anxiao Jiang, Jianer ChenAbstract:Network Planarization has been an important technique in numerous sensornet protocols—such as Greedy Perimeter Stateless Routing (GPSR), topology discovery, data-centric storage, etc.—however the Planarization process itself has been difficult. Known efficient Planarization algorithms exist only for restrictive wireless network models: unit-disk graphs with accurately known location information. In this paper, we study efficient Planarization of wireless sensor networks, and present a novel Planarization method for a more general network model, where sensors can have non-uniform transmission ranges and no location information is needed. Our Planarization algorithms also include a (2+e)-approximation algorithm and an FPT algorithm for the bipartite Planarization problem.
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INFOCOM - Robust Planarization of Unlocalized Wireless Sensor Networks
IEEE INFOCOM 2008 - The 27th Conference on Computer Communications, 2008Co-Authors: Fenghui Zhang, Anxiao Jiang, Jianer ChenAbstract:Wireless sensor networks need very efficient network protocols due to the sensors' limited communication and computation capabilities. Network Planarization - finding a planar subgraph of the network that contains all the nodes - has been a very important technique for many network protocols. It first became the foundation of various well known routing protocols, including GPSR, GOAFR and several other protocols. Since then, it has also been used in numerous other applications, including data-centric storage, network localization, topology discovery, etc. However, an important problem remains: network Planarization itself is very difficult. So far, efficient Planarization algorithms exist only for very restrictive models: the network must be a unit-disk graph, and accurate measurements related to the node locations (e.g., node positions or angles between adjacent links) need to be known. For more practical network models, where the transmission ranges are usually not uniform and sensors cannot obtain their accurate location information via expensive localization devices, no efficient Planarization algorithm is available. In this paper, we present a novel method that robustly planarizes sensor networks of a realistic model: networks with non-uniform transmission ranges and unlocalized sensors (that is, static sensors whose locations are unknown). Our method starts with a simple shortest path between two nodes, and progressively planarizes the whole network. It achieves both efficiency and a good Planarization result. We present two Planarization algorithms for different settings. Our results not only solve the Planarization problem, but also outperform some known results in the graph drawing research field. We demonstrate the practical performance of our method - as well as its application in topology discovery, - through extensive simulations.
A P Shacklock - One of the best experts on this subject based on the ideXlab platform.
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improvement of isolation for mems capacitive switch via membrane Planarization
Sensors and Actuators A-physical, 2005Co-Authors: A Q Liu, Q X Zhang, Arokiaswami Alphones, Lei Zhu, A P ShacklockAbstract:Abstract A new membrane Planarization method on uneven surfaces of sacrificial layer is developed in this work to enhance the isolation of the capacitive shunt switch using microelectromechanical systems (MEMS) technology. In this method, the coplanar waveguide (CPW) slots are filled with the photoresist to planarize the uneven surfaces of the sacrificial layer. The surface contact area between the metal bridge and the dielectric layer is greatly increased after the Planarization. Measurement results show that the isolation can be improved by 2.2 dB at 15 GHz and 10 dB at 40 GHz. In the up-state of switch, the insertion loss is less than 0.4 dB and the return loss is more than −15 dB up to 40 GHz. The proposed Planarization method is relatively simple and cheap compared to the chemical mechanical polish (CMP) in terms of fabrication and engineering implementation.
Fenghui Zhang - One of the best experts on this subject based on the ideXlab platform.
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On the Planarization of Wireless Sensor Networks
Algorithmica, 2010Co-Authors: Fenghui Zhang, Anxiao Jiang, Jianer ChenAbstract:Network Planarization has been an important technique in numerous sensornet protocols—such as Greedy Perimeter Stateless Routing (GPSR), topology discovery, data-centric storage, etc.—however the Planarization process itself has been difficult. Known efficient Planarization algorithms exist only for restrictive wireless network models: unit-disk graphs with accurately known location information. In this paper, we study efficient Planarization of wireless sensor networks, and present a novel Planarization method for a more general network model, where sensors can have non-uniform transmission ranges and no location information is needed. Our Planarization algorithms also include a (2+e)-approximation algorithm and an FPT algorithm for the bipartite Planarization problem.
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INFOCOM - Robust Planarization of Unlocalized Wireless Sensor Networks
IEEE INFOCOM 2008 - The 27th Conference on Computer Communications, 2008Co-Authors: Fenghui Zhang, Anxiao Jiang, Jianer ChenAbstract:Wireless sensor networks need very efficient network protocols due to the sensors' limited communication and computation capabilities. Network Planarization - finding a planar subgraph of the network that contains all the nodes - has been a very important technique for many network protocols. It first became the foundation of various well known routing protocols, including GPSR, GOAFR and several other protocols. Since then, it has also been used in numerous other applications, including data-centric storage, network localization, topology discovery, etc. However, an important problem remains: network Planarization itself is very difficult. So far, efficient Planarization algorithms exist only for very restrictive models: the network must be a unit-disk graph, and accurate measurements related to the node locations (e.g., node positions or angles between adjacent links) need to be known. For more practical network models, where the transmission ranges are usually not uniform and sensors cannot obtain their accurate location information via expensive localization devices, no efficient Planarization algorithm is available. In this paper, we present a novel method that robustly planarizes sensor networks of a realistic model: networks with non-uniform transmission ranges and unlocalized sensors (that is, static sensors whose locations are unknown). Our method starts with a simple shortest path between two nodes, and progressively planarizes the whole network. It achieves both efficiency and a good Planarization result. We present two Planarization algorithms for different settings. Our results not only solve the Planarization problem, but also outperform some known results in the graph drawing research field. We demonstrate the practical performance of our method - as well as its application in topology discovery, - through extensive simulations.
