bluuebunny/crossref_metadata_2025 huggingface dataset:
Accelerated Degradation Modeling and Statistical Analysis of MEMS Device Based on Competing Failure
Authors: Xia Qing , Cao Zong Jie , Wang Yuan Da , Sun Peng
Published: December 2012

Traditional reliability analysis of MEMS devices is based on only one failure mode, but paroxysmal failure and degradation failure are simultaneous on one MEMS device which is called as competing failure modes. Accelerated degradation modeling and parameter estimation based on competing failure modes are elementary contents of reliability analysis, in which paroxysmal failure and degradation failure are integrated in the process of educing reliability function, and elementary theories of reliability and statistics are used. The method of accelerated degradation modeling and parameter estimation is proved to be precise in a simulation of accelerated life test on a kind of MEMS device which have the two failure modes: paroxysmal failure and degradation failure, and they are have relations with stress variable: current.
Experimental Study on Miniature-Refrigeration System
Authors: Yang Juan Juan , Li Ke , Cui Xin Yang
Published: December 2012

A prototype of miniature cooling system was developed, which mainly consists of the miniature compressor from DONG YUAN and a spiral-tube evaporator designed by ourselves. The performances of the prototype with different parameters were tested. The influence of ambient temperature, chilled water temperature on the performance of the cooling system were analyzed. The best operating conditions and the optimum amount of refrigerant were obtained. Conclusions were gotten as follows:1) With environment temperature rising, compression ratio increases, system power consumption increases and refrigerating capacity COP decreases. 2) With chilled water temperature rising, compression ratio and power consumption decrease, refrigerating capacity increases, and COP increases rapidly.3) Paper gets system performance: refrigerating capacity is 63 W, compressor power consumption is 24.5 W, COP value is 2.57. in operation condition: refrigerant amount is 40g, environment temperature is 30°C, chilled water temperature is 40 °C, chilled water mass flow is 45 kg/h.
Synthesis of Zinc Doped-Biphasic Calcium Phosphate Nanopowder via Sol-Gel Method
Authors: Gunawan  , Sopyan I. , Naqshbandi A. , Ramesh S.
Published: December 2012

Biphasic calcium phosphate powders doped with zinc (Zn-doped BCP) were synthesized via sol-gel technique. Different concentrations of Zn have been successfully incorporated into biphasic calcium (BCP) phases namely: 1%, 2%, 3%, 5%, 7%, 10% and 15%. The synthesized powders were calcined at temperatures of 700-900°C. The calcined Zn-doped BCP powders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential and thermogravimetric analysis (TG/DTA) and field-emission scanning electron microscopy (FESEM). X-ray diffraction analysis revealed that the phases present in Zn-doped are hydroxyapatite, β- TCP and parascholzite. Moreover, FTIR analysis of the synthesized powders depicted that the bands of HPO4 increased meanwhile O-H decreased with an increase in the calcination temperature. Field emission scanning electron microscopy (FESEM) results showed the agglomeration of particles into microscale aggregates with size of the agglomerates tending to increase with an increase in the dopant concentration.
Microstructure and Piezoelectric Properties of (0.996-x) K0.5Na0.5NbO3 - 0.004 BiFeO3 - x LiSbO3 Ceramics
Authors: Jiang Min Hong , Liu Xin Yu , Chen Guo Hua , Ma Jia Feng , Zhu Gui Sheng , Xu Ji Wen
Published: December 2012

(0.996-x) K0.5Na0.5NbO3- 0.004 BiFeO3- x LiSbO3 (x =0.00, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07) lead-free piezoelectric ceramics were prepared by the conventional mixed oxide method. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. A morphotropic phase boundary between the orthorhombic and tetragonal phases was identified in the composition range of 0.03 < x < 0.06. With the content of LS increases, the size of the pores significantly decreases. However, adding larger amount of LS makes the pore size increase slightly. The (0.996-x)KNN-0.004 BF-xLS(x=0.05) ceramics possess good electrical properties: d33 = 280 pC/N, kp = 53.3%, Tc = 345 °C, εr = 1613, Tan δ =2.07%. These results show that the ceramic is a promising lead-free piezoelectric material.
Crystal Structure Analysis on Aramid Fiber/Fibrids and Paper by Polarized Light Microscopy
Authors: Zhang Su Feng , Kang Chun Lei
Published: December 2012

The crystal structure of aramid fibers is highly orientated. The structure of aramid fibers with various manufacturing processes and aramid paper sheets were analyzed and observed by using polarized light microscope (PLM). The change and its law of aramid fiber crystal structure in such processes as aramid fiber mamufaturing of aramid fiber/fibrids, forming of aramid paper sheets, and heat treatment were analysed. The relationship between the structural feature of aramid fibers and the performance of aramid paper was also discussed.
Study on Microstructures of Polycarboxylate-Type Superplasticizers with Different Side Chains
Authors: Peng Xiong Yi , Yi Cong Hua , Tang Qian Qian , Qiu Xue Qing
Published: December 2012

Polycarboxylate-type superplasticizers with different side chains and approximative degree of polymerization are synthesized. The microstructures of Polycarboxylate-type superplasticizers in water are studied by fluorescent probe technique, dynamic light scattering (DLS), transmission electron microscopy (TEM) and the self-assembly technique. The results indicate that the formation of hydrophobic microenvironment in PC solution is confirmed. The higher the ratio of long side chains of PC, the stronger the hydrophobic microenvironment formed in PC solution. The Z-Average diameters of aggregation formed in PC solution increase with the increasing of long side chains content. In addition, the size and shape of aggregation is not of uniform distribution, and the reason for this is that association interaction of hydrogen bonding occurs among PC molecules or in the interior of single PC molecule.
Simulation of Dynamic Behaviour of RC Bridge with Steel-Laminated Elastomeric Bearings under High-Energy Mining Tremors
Authors: Dulinska Joanna M. , Szczerba Radoslaw
Published: December 2012

In the paper a detailed analysis of dynamic responses of a reinforced concrete bridge with steel-laminated elastomeric bearings to high-energy mining tremors registered in two main regions of mining activity in Poland (i.e. Upper Silesian Coal Basin and Legnica-Glogow Copper District) was presented. The representative time histories of accelerations from both regions were used as ground motion data in calculations of the dynamic response of the structure. The two-coefficient Mooney-Rivlin model was used as a constitutive model for hyperelastic non-linear elastomeric material. It was proved that the dynamic response of the bridge was strongly dependent not only on the level of vibration amplitudes but on the dominant frequency range of the mining shock typical for the mining region as well. Also the height of elastomeric bearings occurred to have considerable influence on the total dynamic response of the bridge. Two heights of bearings were analyzed: 42 mm and 85 mm. The increase of the height of bearings caused the decrease up to 25 % in the maximal principal stresses obtained in the dynamic analysis. The behaviour of elastomeric material in case of bearings 42 mm high occurred to be strongly non-linear, whereas in case of bearings 85 mm high behaviour of elastomeric material remained almost linear.
Numerical Simulation of the Performance-Based of the Building Fire Protection Safety Evaluation
Authors: Yu Chia Chun , Chen Te Chi , Lin Cherng Shing , Wang Shih Cheng
Published: December 2012

In order to understand the fire safety of the various types of buildings, we need more flexible and efficient performance-estimating methods to verify fire protection safety in various types of buildings. Assuming can utilize computer fire simulation software CFAST / FDS + Evac to analyze Taiwan's domestic fire cases, in order to understand in the different fires heat flow transfer, and toxic smoke diffuse, and human evacuation to escape, and other important fire parameter characteristics, in the building the fire protection safety evaluating to produce the efficiency. This study is used cases of fires in four-story old-style residential and commercial mixed-use buildings to explain building fire performance-based numerical evaluation methods, and to provide quantitative data and reference information in Taiwan performance-based codes creating and the fire protection to project design is helpful in the buildings.
Research on Design Theory and Experimental Validation of Dry Friction Automotive Clutch Based on Failure Mechanism
Authors: Yan Zheng Feng , Liu Wen Jun
Published: December 2012

As a key component of vehicle, automotive clutch remained high failure rate, meanwhile, with the development of engine and vehicle technology, functional characteristics of automotive clutch such as comfort, durability and reliability demanded much higher. Objective of the study is to establish the correspondence relationship between failures and design theory and experimental methods, reduce failure rate and improve product reliability. In order to create a system approach of problem-solving, we collected clutch failure information and classified according to clutch functional requirements and mechanical design principles. Then we used RCA (root cause analysis) and quality management tools to analyze the cause of failures, used QFD (quality function development) and DFMEA (design failure mode effects analysis) method to protocol the corresponding control measures to improve the existing design theory and experimental methods. The study also can be applied to more complex systems such as dry dual clutch module and dual-mass flywheel damper.
Kinetics of Bamboo Fiber Hydrolysis Reaction in Saturated Formic Acid
Authors: Zhuang Jun Ping , Lin Lu , Pang Chun Sheng , Liu Ying
Published: December 2012

Kinetic models can have practical applications for the optimization of the process and performance analysis, or economic estimations, so investigate the bamboo fiber kinetics is necessary. In this paper, effects of temperature and time on bamboo fiber hydrolysis in saturated formic acid with 4% hydrochloric acid solution reaction kinetics have been investigated. The rate constants, average apparent activation energy and frequency factors were evaluated according to the Arrhenius equation. The results showed that the hydrolysis velocities of bamboo fiber were 1.63×10-2 h-1 at 55 °C, 2.59×10-2 h-1 at 60 °C, 4.56×10-2 h-1 at 65 °C, 6.75×10-2 h-1 at 70 °C and 0.10 h-1 at 75 °C in formic acid solution with 4 % hydrochloric acid. The degradation velocities of glucose were 6.57×10-3 h-1 at 55 °C, 1.98×10-2 h-1 at 60 °C, 2.53×10-2 h-1 at 65 °C, 7.47×10-2 h-1 at 70 °C and 0.14 h-1 at 75 °C. The pre-exponential factor of Arrhenius equation of bamboo fiber hydrolysis reaction and glucose decomposition was 1.48×1014 h-1 and 2.32×1020 h-1 respectively. The activation energy of bamboo fiber hydrolysis was 87.65kJ/mol, and the activation energy of glucose degradation was 141.44kJ/mol.
The Theories and Application of Numerical Simulation with Smoothed Particle Hydrodynamics Method
Authors: Zhou Hui Lin , Yu Hui Yong , Pang Ming Hua
Published: December 2012

The Smoothed Particle Hydrodynamics (SPH) method is a very important method to resolve hypervelocity problems and the basic theory of SPH method is introduced here. Then the three dimensional hypervelocity impact problems are simulated by using the model of chair. The results of SPH analysis show that (SPH) method is a numerical calculation method to resolve hypervelocity problems without mesh model but the particle model must be getting to calculate and the program code is less than other method. By analysis the results of the simulation is reasonable and very similar to the test result. It can be concluded that the advantages of SPH demonstrated make it a good and an ideal method to simulate the impact problem and other problems.
Finite Element Analysis of the Main Spindle of the Gold Ornaments Chain Forming Device
Authors: Yang Jia Peng , Zhang Chun Liang , Zhu Hou Yao
Published: December 2012

With China's rapid economic development, domestic jewelry consumption has maintained a high growth rate. Jewelery manufacturing equipment is always behind, seriously hampered the development of the industry. For this situation, the author carried out a series of gold automated processing equipment. In this paper, based on the design of a gold-decorated chain molding equipment, using ANSYS software to do finite element analysis on the spindle three-dimensional model of the gold ornaments chain forming equipment. Because the spindle have great impact in the gold processing accuracy for deformation and vibration.
A Novel Bogus Data Detection and Filtering Scheme for Wireless Sensor Networks
Authors: Zhang Zhi Ming , Xiong Xiao Yong , Jiang Chang Gen
Published: December 2012

In many scenarios, wireless sensor networks are deployed in hostile environments. Adversaries could easily compromise sensor node, and bogus data could be injected into the network through the compromised sensor nodes, which decreases the accuracy of the sensing data and wastes scarce energy resources of the networks. In this paper, a novel bogus data detection and filtering scheme for wireless sensor networks was proposed based on one-way hash function. In the proposed scheme, if the sensing node was compromised, the based station could verify the endorsement report, and if the compromised forwarding node modified the report packet, the bogus data could be verified by the next forwarding node, and the modified report packet would be discarded. The analysis shows that the proposed scheme not only provides a high security level but also can detect most bogus data and achieve energy savings.
Systematic Research on Building Strategy-Oriented Management System of Local Party and Government Leaders’ Environmental – Protection Performances
Authors: Zuo Jian Lin
Published: December 2012

This paper analyzes the functional requirements for directing, communicating, distinguishing and evaluating of strategy-oriented management system of local party and government leaders’ performances, and provides the design thoughts of building the management system from four aspects: organization and responsibility system of managing environmental performances of local party and government leaders, decomposing system of local government’s strategic goals, process system of management of local party and government leaders' performances and basic guarantee system of management of the leaders’ performances; it also points out that in building strategy-oriented management system of local party and government leaders’ energy-saving and emission-reducing performances, the work of one center, four key sectors and six important decisions should be done well.
A New Algorithm of Path Planning Based on Local Data
Authors: Zhou Zi Wei , O Yang Xin Yu , Xu Wang Bao , Cui Nai Dong
Published: December 2012

A novel new algorithm of path planning is proposed for the robot path planning based on the local data map in the robot autonomous navigation. The algorithm is used to search for the local optimal path from the current position of the robot to the target according to the known sensor data. If the robot cannot reach the target directly, the temporary target point which the robot can reach will be set up according to the optimal path. The algorithm is effective under the complicated unknown environment and moving obstacle situation which fast searching speed, it can be adapted into the practical applications and the multi-robot harmony easily. The simulation result shows that this method can provide a better planning path by comparing with the traditional planning algorithms such as artificial potential field and wall-following
Present Research Situation and Future Perspectives of Grinding Process Simulation System
Authors: Tang Hao , Deng Zhao Hui , Liu Wei , Wan Lin Lin , Wu Qiao Ping
Published: December 2012

Grinding, as the last process of most products, directly affect the machining accuracy and surface quality of the product. Multi-parameter input and output and nonlinear mapping between the parameters of the grinding process play the most important part of computer simulation applied to grinding process. In this paper, the theory of computer simulation was introduced and a detail research on status of grinding process model and grinding process simulation system at foreign and domestic were elaborated, focused on the foreign academic research in this area. In the end, the paper presents an outlook of the research of grinding process simulation system.
Low Temperature Preparation of ZrC Coatings on C/C Composite via Molten Salt Reaction
Authors: Chen Si’an , Hu Hai Feng , Zhang Yu Di , Zhang Chang Rui , Li Guang De
Published: December 2012

Zirconium carbide (ZrC) coatings were prepared on C/C composite via molten salt reaction process at relatively low temperatures of 800-1000°C. During the reaction process, potassium fluorozirconate (K2ZrF6) played a role transporting zirconium from the molten salt to the C/C composite surface. Elevating reaction temperature increased the growth rate of coatings, simultaneously leaded to rougher coatings. The coatings growth rate increased with reaction time at first and then decreased gradually. The ZrC coatings prepared at 900°C for 5h was ~2m thickness. At the early stage, the low solubility of zirconium in the molten salt leaded to the low coatings growth rate. Secondly, the growth rate of the ZrC coatings was controlled by the chemical reaction between C/C composites and zirconium once zirconium was saturated in the molten salts. Thirdly, the control step of coatings formation turned into the diffusion of carbon through the formed ZrC coatings and which leaded to a gradual decrease of growth rate.
Optimization of Organic Fibres%[Kevlar/Arobocel/Acrylic] in NAO Brake Pad Application and its Effect on Thermal Stability & Friction Characteristics
Authors: Balaji M.A. Sai , Kalaichelvan K.
Published: December 2012

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.
Crack Behavior of Si-Doped GaAs Crystals Grown by Pulling-Down Method
Authors: Fang Yong Zheng , Jin Min , He Qing Bo , Shen Hui , Jiang Guo Jian , Xu Jia Yue
Published: December 2012

The crack behavior of Si-doped GaAs crystals produced by a novel pulling-down method was investigated. Some cracks were observed in the crystal tail part and no twins or polycrystals were observed. The cracking mechanism was discussed considering the growth parameters, such as the pulling-down rate, annealing time and cooling speed of the furnace. The crystal was easily broken if the cooling rate was too fast. To avoid cracking, the temperature profile and the growth parameters had been optimized. The cleavage property of the GaAs crystal was strongly related to its atomic arrangement and corresponding electron density map. Ultrasonic vibration or mechanical machine would make the crystal cleaved along (110) plane. GaAs crystal displayed a strong anisotropic crack property under the force of microindentation test.
Advanced Ceramic / Metal Polymer Multilayered Coatings for Industrial Applications
Authors: Rempp A. , Widmann M. , Killinger A. , Gadow R.
Published: December 2012

For the reduction or complete compensation of grease and lubricants in mechanical engineering, special combined coatings for machine components with extended tribological and chemical properties have been developed. Ceramic or metal polymer coating systems are a combination of thermally sprayed hard materials with polymers containing solid lubricants of inorganic and fluorpolymeric origin (i.e. lubricant lacquers). The thermally sprayed hard material guarantees hardness and wear resistance and the lubricant lacquer causes low friction coefficients and smooth gliding performance. In this paper, results of different polymer and multicoating systems on steel substrates are presented. Molybdenum, a cermet based on tungsten carbide, a copper based alloy and chromia were used as wear resistant materials and deposited by means of High Velocity Flame Spraying (HVOF/HVLF). On these surfaces, lubricant lacquers of some μm thickness were deposited by air spraying. The life-time and the friction coefficient of the resulting layers depending on surface texture of the hard material or substrate and lacquer composition were determined using a twin disc tester under dry sliding conditions.
Microstructure and High-Temperature Oxidation-Resistant Performance of Several Silicide Coatings on Nb-Ti-Si Based Alloy Prepared by Pack Cementation Process
Authors: Li Jing , Guo Xi Ping
Published: December 2012

The microstructure and high-temperature oxidation-resistant performance of several silicide coatings on an Nb-Ti-Si based alloy were revealed in the present work. These silicide coatings were prepared respectively at 1250°C for 8 h by pack siliconizing process, Si-Y co-deposition process and Si-Al-Y co-deposition process (with different Al contents in the packs). The results showed that the purely siliconized coating was composed of a (Ti,Nb)5Si3 ouer layer, a (Nb,X)Si2 (X represents Ti, Cr and Hf elements) middle layer and a (Ti,Nb)5Si4 inner layer. A thicker and more compact double-layer structure including a (Nb,X)Si2 outer layer and a (Ti,Nb)5Si4 inner layer was observed in the Si-Y co-deposition coating. In addition, a higher Y content (about 0.34 at. %) in the outer layer of the Si-Y co-deposition coating was obtained, while the Y content was only about 0.06 at. % in the purely siliconized coating. The Si-Al-Y co-deposition coating possessed a (Nb,X)Si2 outer layer, a (Ti,Nb)5Si4 middle layer and an Al, Cr-rich inner layer. A suitable addition of Al powders (5 wt. %) in the packs was beneficial to thicken the (Nb,X)Si2 outer layer, while a sharp reduction in the coating thickness was found when excess Al powders (10 wt. %) was added in the packs. However, compared with the former coating, the later coating prepared with more Al powders in the packs resulted in a slight increase in the content of Al and Y in the (Nb,X)Si2 outer layer from about 0.21 and 0.54 at. % to 0.87 and 0.79 at. % respectively. The thickness and microstructure of the scales formed on above four coatings upon oxidation at 1250°C for either 5 h or 100 h were comparatively investigated. The oxidation resistance of these silicide-type coatings was notably enhanced by the addition of Y and Al. The Si-Al-Y co-deposition coating, which was prepared with 5 wt. % Al powders in the pack, possessed the best oxidation resistance due to its optimum dense and continuous scale and compact coating remained. Keywords: Nb-Ti-Si based alloy; coating; microstructure; oxidation-resistant perfor-mance *Corresponding author. Tel./fax: +86 29 88494873. E-mail address: xpguo@nwpu.edu.cn (X. Guo).
Development of Bioactive Hydroxyapatite Coatings on Titanium Alloys
Authors: Carradò Adele
Published: December 2012

Bioactive coatings are currently manufacturing using plasma-sprayed technique on metal implant surfaces in order to optimize bone-implant interactions. Nevertheless, some problems exist with coating process, e.g. poor interfacial adhesion, modification of coating properties, and the lack of an existing coating standard. In order to overcome some of the problems with the plasma-spraying process, researchers are investigating other experimental coating methods to enhance the adhesion and to control the coating properties. This paper will discuss the advantages and disadvantages of plasma spraying and the experimental coating processes as pulsed laser deposition as well as spin-coated sol-gel.
Characterization and Tribological Performance of Cu-Based Intermetallic Layers
Authors: Joseph J. , Fabijanic Daniel M.
Published: December 2012

Fluidized bed reactor chemical vapor deposition (FBR-CVD) has been used to enrich the surface of oxygen free high conductivity (OFHC) copper with titanium, silicon and aluminum. This technique enables the production of coherent and adherent intermetallic surface layers of uniform thickness and high hardness. The characterization of the coatings was performed using backscatter scanning electron microscopy (BS-SEM), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDOES) and micro-hardness. The tribological properties of the coatings in dry sliding contact with steel were evaluated by pin-on-disc wear testing.
Characterisation of Interfacial Adhesion of Thin Film/Substrate Systems Using Indentation-Induced Delamination: A Focused Review
Authors: Lu Ming Yuan , Xie Hong Tao , Huang Han
Published: December 2012

This review summarized the research works on the characterisation of interfacial adhesion in thin film/substrate bilayer structure by use of indentation testing. It focused on the delamination mechanics between a thin film and a substrate induced by indentation and the quantitative characterisation of interfacial strength in such bilayer systems. Three major techniques were introduced, namely conventional indentation, cross-sectional indentation and acoustic emission assisted indentation. A number of theoretical models and finite element simulation studies were discussed, in association with the experimental investigations. Key words:Thin film, bilayer, delamination, adhesion, indentation, acoustic emission
Unique Size-Dependent Challenges for BEOL Cleans in the Patterning of Sub-20 nm Features
Authors: Singh Kanwal Jit
Published: December 2012

BEOL Cleans has been and continues to be one of the most mysterious black boxes of semiconductor manufacturing. It has the unenviable task of removing post-plasma processing polymer residues, being compatible with ultra low-k dielectric materials that continue to scale k-value at the expense of material strength, and ensuring that any formulation that accomplishes the above objectives is also compatible with Cu and all other metals on the wafer used for liners or caps. In order to meet the performance requirements of next generation devices, Moore's law mandates continued scaling of dimensions with the additional challenges of size-dependent complexities for BEOL cleans development. Patterning of sub-20 nm features on thin ILD stacks suffers from the problems of etch-induced line undulation [1, 2] and cleans-induced pattern collapse [3]. High aspect ratio's, non-uniform drying, surface tension and low material strength have all been implicated as the root cause for pattern collapse during cleans [4]. Classical equations used to describe pattern collapse for resist lines that rely on 2D beam theory and finite element modeling [5] are not as applicable to patterned low-k dielectrics because material changes such as sidewall polymer residues, lowering of Young's modulus and changing pattern densities present different solid surfaces with widely varying wettability and diffusivity parameters [6, .
Determination of Surface Energy Characteristics of Plasma Processed Ultra Low-K Dielectrics for Optimized Wetting in Wet Chemical Plasma Etch Residue Removal
Authors: Ahner Nicole , Zimmermann Sven , Schaller Matthias , Schulz Stefan E.
Published: December 2012

The integration of porous ultra low dielectric constant materials (ULK) for isolation within the interconnect system of integrated circuits is a promising approach to reduce RC-delays and crosstalk due to shrinking feature sizes [1]. Actually the focus is on porous CVD-SiCOH materials, which consist of a Si-O-Si backbone and organic species (e.g. CH3) to lower polarizability and prevent moisture uptake to remarkably decrease the k-value [2]. The integration of porous low-k materials is very challenging, especially looking at patterning, resist stripping and etch residue removal, where commonly plasma processing has been applied. But plasma processing of ULK materials, especially using oxygen plasmas, is known to degrade electrical, optical and structural material properties by removing carbon from the film and densification of the surface near areas of the ULK [5]. Carbon depletion may also lead to the incorporation of-OH groups, which easily form silanols and therefore increase moisture absorption and k-values [2]. Besides the development of nondamaging plasma processes, wet cleaning is a promising alternative to avoid ULK damage while removing organic plasma etch residues. Additionally wet cleaning steps are always necessary to remove inorganic residues, which do not form volatile reaction products and can therefore not be removed by plasma processing.
Analysis of Oxidized Copper Surface and its Evolution
Authors: Milanesi Francesca , Pipia Francesco , Spadoni Simona , Grasso Salvo , Ravizza Enrica , Pistoni Mario , Alessandri Mauro
Published: December 2012

The interest towards Copper RDL (Re-Distribution Layer) is due to some advantages related to this approach. First of all it is cheaper than conventional Damascene approach; moreover it allows thicknesses as high as 10µm or more whereas with Damascene architecture Cu thickness is limited to <5µm. Figure 1 introduces the architecture concept, which is based on a quite long ECD growth on a substrate with patterned PhotoResist.
Introduction of a Dynamic Corrosion Inhibitor for Copper Interconnect Cleaning
Authors: Otake Atsushi , Kuroda Akira , Luo Roger , Bernatis Paul R.
Published: December 2012

Copper has become the material of choice for the interconnects in semiconductor devices due to its low resistance and ease of processing [1]. Device fabrication with copper requires electrochemical deposition and chemical mechanical planarization (CMP). Since the polished copper surface generated during CMP is considered to be one of the most important factors which determine the performance of the interconnect, post-CMP cleaners must efficiently remove residues generated by the polishing process [2]. CMP slurries and post-CMP cleaners frequently include corrosion inhibitors to form a protecting layer on copper surface. If a thick organic film remains on copper after cleaning processes, it can have unfavorable effects on performance of copper interconnects. To minimize this issue, the authors earlier described a corrosion inhibitor which formed a very thin protective layer and that was easily removed by plasma treatment [3, 4].
One-Step Wet Clean Removal of Post-Etch Fluoropolymer Residues
Authors: Gemmill William R. , Kesters Els , Le Quoc Toan
Published: December 2012

Back end of the line processing requires removal of deposited polymers resulting from etch processes. These polymers typically exist on the whole of the pattern including the dielectric sidewalls and can be removed by wet cleans or a combination of wet cleans and plasma treatments. When a porous dielectric is present these residues cannot be efficiently removed using plasma or certain wet cleans without potentially damaging the underlying porous dielectric layer. Therefore there exists a need for a one-step wet clean that can completely remove the residues without damaging the porous dielectric. Previous work has shown that a combination of a UV pretreatment followed by a wet clean can remove these residues [1]. These residues are composed of CF, -CF2, and CF3 groups as described by X-ray photoelectron spectroscopy (XPS). In an effort to improve the manufacturing viability of such a process we have undertaken a study to develop a one-step wet clean for fluoropolymer removal. Utilizing a blanket checkerboard pattern with a model fluoropolymer deposited on a porous low-κ substrate we have demonstrated the one-step wet clean of the aforementioned fluoropolymer while maintaining compatibility with the pristine and etch processed porous low-k dielectric.
Determination of Fluoride Concentration on Aluminum Bond Pads Using Liquid Phase Extraction Ion Chromatography
Authors: Te Brake Roy , Knotter D. Martin , Leenders–van Hees Miranda
Published: December 2012

Fluoride contamination on aluminum bond pads is a major issue in the reliability of semiconductor products [. Fluoride contamination can lead to bond pad corrosion, bond pad staining [, (see Figure 1) and bad wire bond quality [. In the ITRS a maximum allowable fluoride concentration in the aluminum wafer process environment is listed [. However, it is not only the air concentration that determines the criticality, but also the exposure time, humidity, and if there is a fluoride source available that can maintain an increased air concentration of fluoride. Therefore, it is more valuable to know at what surface concentrations fluoride contamination on aluminum surfaces become an issue.
Development of Integrated Wet Cleans for 3D-SIC Technologies
Authors: Suhard Samuel , Simms Ihsan , Brown Ian H. , Shogo Mizota , Koji Kagawa , Claes Martine , Buisson Thibault , Jourdain Anne , Beyer Gerald , De Gendt Stefan
Published: December 2012

3D stacked IC (3D-SIC) is one of the main approaches within 3D technologies as it is the most mature and economically viable technology and provides the highest through silicon via density. Enabling 3D SIC requires the modification of standard IC process flows by adding several process modules, such as through silicon via (TSV), wafer bonding and thinning, prior backside processing (e.g. Cu nails exposure), micro bumps formation for the front side and/or the backside and finally stacking to another chips [. Within the 3D-SIC technology developed at IMEC, surface control and preparation by means of wet clean and wet etch are essential steps notably in two key process modules: wafer thinning and micro bump formation.
Acoustic Bubbles: Control and Interaction with Particles Adhered to a Solid Substrate
Authors: Mettin Robert , Frommhold P.E. , Xi X. , Cegla F. , Okorn-Schmidt H. , Lippert A. , Holsteyns F.
Published: December 2012

Applications of acoustic cavitation [ frequently suffer from certain random aspects (e.g., stochastic bubble nucleation events) as well as from its sensitivity to external parameters (like gas content in the liquid). This renders for example a prediction of bubble distributions in size and space still a difficult task. To improve this situation by a better understanding of the fundamentals, a "bottom-up" approach has recently been followed which tried to model collective bubble phenomena and bubble structures on the basis of single bubbles and their interaction [. If the behavior of individual bubbles can be well captured by the models, it is hoped to gain significant insight into a larger system of acoustically driven bubbles. Indeed, several aspects of multi-bubble systems and structures could be explained by single bubble dynamics, for instance by the inversion of the primary Bjerknes force in strong ultrasonic fields. Nevertheless, many details of bubble dynamics stay partly unclear, and considerable efforts are undertaken to improve our understanding and to optimize applications of acoustic bubbles.
Acoustic Cavitation Behavior in Isopropyl Alcohol Added Cleaning Solution
Authors: Kang Bong Kyun , Jeong Ji Hyun , Kim Min Su , Sohn Hong Seong , Busnaina Ahmed A. , Park Jin Goo
Published: December 2012

As the semiconductor manufacturing technology for ultra-high integration devices continue to shrink beyond 32 nm, stringent measures have to be taken to get damage free patterns during the cleaning process. The patterns are no longer cleaned with the megasonic (MS) irradiation in the advanced device node because of severe pattern damages caused by cleaning. Recently, several investigations are carried out to control the cavitation effects of megasonic to reduce the pattern damages. The mechanism of damage caused by an unstable acoustic bubble motion was mainly attributed to the high sound pressure associated with violent bubble collapse [1]. In order to characterize the dominant factors affecting the cavitation, MS cleaning was conducted with various dissolved gas concentrations in water. It was reported that the cavitation phenomena relating to particle removal efficiency (PRE) and pattern damage were considerably changed with the addition of a specific gas [2]. This changing behavior may be due to the difference in the physical properties of dissolved gases associated with acoustic bubble growth rate as a function of their concentration. In particular, cavitation effects induced during MS cleaning was controlled by adjusting the acoustic bubble growth rate. Also the change of bubble growth rate is well explained by both rectified diffusion for single bubble and bubble coalescence for multi-bubble, respectively. Similarly, it is well-known that surface active solute (SAS) in the ultrasound field plays an important role in controlling the cavitation effects. A detailed explanation of the acoustic bubble growth rate, cavitation threshold and their relationship with various types of SAS and concentration of biomedical and chemical reactions perspective have been reported elsewhere [3,4]. Their studies demonstrated that the change of cavitation effects depends not only on the chain length of alcohol in the solution but also on the physical properties such as surface tension and viscosity of SAS solutions.
Evaluation of Very Dilute Alkaline Solutions for Wafer Cleaning with Megasonic Irradiation
Authors: Jeong Ji Hyun , Kang Bong Kyun , Kim Min Su , Sohn Hong Seong , Busnaina Ahmed A. , Park Jin Goo
Published: December 2012

In the semiconductor wafer cleaning, ammonium hydroxide based APM (ammonium peroxide mixture) has been widely used to remove particles and organic contaminants [. However as the film thickness and line width of semiconductor structure scales down rapidly, the material losses by etching reaction of alkaline chemicals can cause serious problem in yield loss due to electric failure. The presence of H2O2 could enhance the material loss on silicon wafer. Very dilute alkaline chemicals might be of interest since it could minimize any possible ionic contamination or chemical residues from chemicals as long as we control the surface roughness and particle removal efficiency. Also the characterization of these very dilute alkaline chemicals will be very useful for particle removal in gas dissolved DI water.
Removal of Fine Particle Using SAPS Technology and Functional Water
Authors: Wang David H. , Ma Yue , Chen Fu Ping , Xie Liang Zhi , Wang Xi , Zhang Xiao Yan , Lee Ju Young , Kim Dong Joo , Lee Jeong Yun , Leem Pyo , Choi Geun Min
Published: December 2012

Space alternated phase shift (SAPS) megasonic technology incorporating with functional water, with dissolving gases H2 or N2, was applied to remove fine particle in wet cleaning processes of semiconductor manufacturing in this study. The performances of particle removal were investigated quantitatively by varying the parameters of functional water and megasonic energy. The optimized cleaning performance was further proved with significant yield improvement of mass production by comparison with other main cleaning technology.
Physical Cleaning Enhancement Using Advanced Spray with Uniform Droplet Control
Authors: Chien Ying Hsueh Chang , Yeh Matt , Ku Scott , Yang C.M. , Chen C.C. , Jang S.M. , Izumoto K. , Sotoku K. , Tanaka T. , Sato M. , Shirakawa H. , Tanaka M.
Published: December 2012

In semiconductor device manufacturing, single wafer processors are widely used in not only BEOL process but also in FEOL process for 2X devices to improve the cleaning efficiency and get the higher productivity. Because the scaled down devices require the minimum substrate loss in the cleaning steps, the physical force by a dual fluid spray is still the main position to improve the cleaning efficiency at the moment comparing with chemical effects as the dissolution of contaminants and/or the lift off of particles. Sato, et al., reported that the relationship between particle removal and droplet characteristics linked to the droplet energy densityEdas following equation [. The kinetic energyEkof droplet is calculated from droplet diameterdand velocityv, as shown in Equation 1.
CO2-Dissolved Water Cleans for 2xnm-Node Silicon Devices in a Single Wafer Megasonic System
Authors: Park Chan Geun , Sohn Hong Seong
Published: December 2012

Megasonic cleans have been applied to remove defects such as particles and polymer/resist residues in silicon wafer fabrication of IC devices. However, with the shrink of device technology node, megasonic cleans are being challenged to maintain high cleaning efficiency promoted by streaming force of stable cavitation for the smaller particles without producing pattern collapse caused by violent implosions of transient cavities [. S. Kumari et al. reported that CO2-dissolved water (CO2 DIW) was potentially able to suppress wafer damage during megasonic exposure by minimizing unrestrained explosion of transient cavities. This is accomplished through the study on Sonoluninescence (SL), the phenomenon of release of light when liquid is irradiated by sound wafers of sufficient intensity, as a sensitive indicator of cavitation events [2, . This paper compares the effects of CO2 dissolution on particle removal efficiency (PRE) and pattern collapse in a range of megasonic power with >100nm-size Si3N4 particles and 2xnm node line/space-pattern, respectively to N2-gasified water (N2 DIW).
Effect of the Surface/Water Chemistry on the Creation of Watermarks
Authors: Belmiloud N. , Tamaddon A.H. , Mertens Paul W. , Struyf Herbert
Published: December 2012

Although evaporation as a pure bulk phase transformation is well understood, when one adds solutes to the liquid, or brings the liquid into contact with a substrate, we obtain a new and rich variety of possible behaviors that we can access experimentally to better understand the drying dynamics of residual water droplets. Evaporation of sessile droplets with a small contact angle (below 90°) is studied here extensively on silicon substrates. We focused our work on the origin of the creation of watermarks on silicon wafers. A thorough understanding of droplet evaporation is of vital importance for examining the drying rate, the flow patterns observed inside drying drops, and the residual deposits. The concentration of each potential dissolved species (e.g. silica or silicic acid) can also be predicted and confronted to their solubility. We developed a theoretical model to predict the evaporation rate and the behavior of submillimetric droplets taking into account the characteristics of the ambient and the substrate during the drying process. We discuss also the topology of watermarks on silicon wafers in the case of a predominant evaporation phenomenon.
Wetting Challenges in Cleaning of High Aspect Ratio Nano-Structures
Authors: Xu Xiu Mei , Vereecke Guy , van den Hoogen Erik , Smeers Jens , Armini Silvia , Delande Tinne , Struyf Herbert
Published: December 2012

In semiconductor fabrication, pattern collapse of high aspect ratio structures after wet processing has been a critical issue and attracted a lot of interest. On the other hand, very little attention is spent on the potential wetting issues as feature dimensions are continuously scaled down and novel materials with different wetting properties are used in new technology nodes. In this work we investigate the wettability of nanopatterned silicon substrates with different surface modifications.
Improved Drying Technology of Single Wafer Tool by Using Hot IPA/DIW
Authors: Kim Chang Hyun , Yun Min Sang , Hwang Tae Ho , Nam Chang Hyeon , Kim Si Chul , Roh Jung Hun , Lee Mong Sup , An Jung Soo
Published: December 2012

As the DRAM design rule has been smaller, the leaning normally occurred in storage pattern with high aspect ratio also appears in STI (shallow trench isolation) pattern of sub 4Xnm device. IPA (isopropyl alcohol) showing the excellent ability to replace DIW (de-ionized water) is necessary in order to meet the leaning free condition, because the spin drying method cannot satisfy with leaning free condition.
Effects of Substrate Temperature on the Leaning of Micropatterns during Rinse-Dry Process
Authors: Kim Tae Hong , Kim Jung Chul , Kim Seung Ho , Kim Ho Young
Published: December 2012

The spin drying, in which a rinsing liquid deposited on a wafer is rapidly dried by wafer spinning, is an essential step in semiconductor manufacturing process. While the liquid evaporates, its meniscus straddles neighboring submicron-size patterns. Then the capillary effects that pull the patterns together may lead to direct contact of the patterns, which is referred to as pattern leaning, a problem becoming more and more serious as the pattern size shrinks and the aspect ratio of the patterns increases. The interaction between elastic structures and capillary forces, orelasto-capillarity[1, 2], has long been observed in nature but just starts to find its applications in artificial system. It is particularly relevant to the fabrication of high-aspect-ratio structures in semiconductor manufacturing [3, 4, 5] because it is responsible for the stiction of patterns in rinsing and drying process. Here we visualize the micropattern leaning process and evaluate the role of substrate temperature in preventing collapse of patterns.
New Chemical Vapor Delivery Systems for Surface Cleaning
Authors: Alvarez Jr Dan , Spiegelman Jeff , Heinlein Ed , Ramos Chris , Holmes Russell J. , Shamsi Zohreh
Published: December 2012

Conventional aqueous wet cleaning methods in semiconductor manufacturing are facing tremendous challenges, with decreasing line widths and high aspects ratio features on the order of a few nanometers. Water and other liquids have surface tensions that frequently prevent complete penetration into nanometer-sized trenches and vias now being fabricated on semiconductor wafers and other substrates. This problem is accentuated by the fact that particle sizes leading to Killer defects are now on the order of 10 nm or less. Nanometer-sized particles can adhere to a surface with a relatively strong force of over a million times its weight. An effective cleaning technique for submicron particle removal will require complete penetration of the device features to surround and dislodge particles, but at the same time not damage the features or etch the surface.