bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth Control of GaAs Epilayers with Specular Surface on Nonmisoriented (111)B Substrates by MBE
Authors: Yang Ruixia , Wu Yibin , Niu Chenliang , Yang Fan
Published: March 2010

GaAs epilayers with specular surface are successfully obtained on nonmisoriented GaAs(111)B substrates by conventional MBE. The growth control achieved via in situ, real time monitoring of the specular beam intensity of reflection high-energy electron diffraction (RHEED) on static and dynamic GaAs(111)B surfaces is reported. The dependence of GaAs(111)B surface reconstruction phases on growth parameters is discussed. The proper starting surface phase (√19×√19) is identified by RHEED for the growth of mirror-smooth epilayers. Growth conditions are optimized in terms of the static surface phase diagram and the temporal RHEED intensity.
From 2-Dimensional Lithography To 3-Dimensional Structures
Authors: Van Zeijl Henk , Wei Jia , Shen Chenggang , Verhaar Theo M. , Maury Pascale , Sarro Lina M.
Published: March 2010

Lithography for IC device fabrication is a high volume high accuracy production technology. Such production characteristics are also attractive for MEMS and 3 dimensional (3D) integration processes. However, advanced lithography has a strong 2 dimensional (2D) nature and is not optimized to fabricate 3D structures. In this work, 5 exposure and etch strategies are discussed to use advanced 2D lithography to fabricate 3D structures.
Litho/Design Co-Optimization and Area Scaling for the 22-nm Logic Node
Authors: Blatchford James W. , Prins Steven L. , Jessen Scott W. , Dam Thuc , Baik KiHo , Pang Linyong , Gleason Bob
Published: March 2010

We present a comprehensive study of area scaling for 22nm-logic-node routed metal/via layers as a function of route pitch and patterning strategy in both single-exposure (SE) and double-patterning (DP) regimes. For each candidate route pitch (88-56nm), we determine an optimal illumination scheme and develop layout rules for the metal layers. A perturbative area model is used to approximate the impact of the candidate rule set on area scaling. For the most promising SE case, we apply a novel 'source/design optimization' technique to further optimize illumination and rules, wherein we extend the source-mask optimization approach (1) by allowing design rules to vary in the analysis. We demonstrate that the optimal area scaling achievable with DP techniques can be vastly superior to SE, and therefore may justify the associated additional cost per wafer.
Mask Cleaning in EUV and Nano-Imprint Lithography
Authors: Zhang Yuan , Singh Sherjang , Chen Ssuwei , Dress Peter , Dietze Uwe
Published: March 2010

Extreme Ultra-Violet Lithography (EUVL) and Nano-Imprint Lithography (NIL) are the two leading candidates for next generation lithography (NGL). New image projection methods and materials have led to inherent changes in the way EUVL masks and NIL templates are manufactured, handled, stored and processed. Where a pellicle is used to protect the patterned area of a conventional optical mask, both EUV masks and NIL templates are without surface protection and thus more susceptible to contamination during transportation, storage and the photolithography process. Zero tolerance levels for impurities, particles, pattern defects and/or surface layer damage is driving the development of new cleaning technology that can eliminate contamination and preserve the integrity of the mask/ template. In this paper, key cleaning challenges for EUV masks and NIL templates are addressed and novel cleaning techniques are demonstrated that remove contamination without pattern damage or surface properties changes.
Polymer-Bound PAGs for EUV Lithography
Authors: Thackeray James W. , Aqad Emad , Kang Su Jin , Spear-Alfonso Kathleen
Published: March 2010

This paper discusses the relative merits of traditional PAG blend resist approach vs a novel Polymer-bound PAG resist approach. In looking at EUV exposures it is shown that the Polymer-bound PAG approach possesses advantages in LWR and Resolution over a PAG blend resist approach. The Polymer-bound PAG approach achieves 24nm half pitch resolution with an LWR of 3.8nm and a photospeed of 11mJ. The Polymeric PAG approach also possesses higher exposure latitude vs a PAG blend resist. Although still maturing, it is felt that polymer-bound PAG-based resists will become quite useful at the 22nm node and below.
Comparative Study of Photosensitive Versus Non-Photosensitive Developer-Soluble Bottom Anti-Reflective Coating Systems
Authors: Lowes Joyce A. , Stroud C. , Guerrero A. , Washburn C. , Raj P.
Published: March 2010

Developer-soluble bottom anti-reflective coatings (DBARCs) were originally designed for use in implant lithography processes. Throughout the development cycle, two main DBARC platforms emerged, non-photosensitive DBARC (non-PS DBARC) and photosensitive DBARC (PS DBARC). While both platforms have been able to achieve acceptable performance for implant processes, each has advantages and disadvantages. The characteristics of each system are used to recommend a platform for use in various implant processes. DBARC processes are now being compared to single-layer resist and dry BARC processes due to additional applications such as wet-etch layers for high-k dielectric metal gate (HKMG). Integrating a new technology into production is complicated. Therefore, for each of these new applications, the different DBARC platforms have been reviewed to compare performance. The analysis allows us to recommend a DBARC and a favorable process for each application, thereby decreasing development time and cost.
Source and Mask Co-Optimization Using a Gradient Based Method in Optical Lithography
Authors: Peng Yao , Zhang Jinyu , Wang Yan , Yu Zhiping
Published: March 2010

With the technology node entering 45nm and below and the delay of the EUV lithography, the resolution enhancement techniques (RET) has been considered indispensable to extend the life time of conventional 193nm lithography. Traditional RETs, for example, optical proximity correction (OPC), phase-shifting mask (PSM), inverse lithography technique (ILT) and so on, use a fixed source thus limiting the degrees of freedom during the mask pattern optimization. To overcome the restriction, recently, source and mask co-optimization (SMO) has been proposed as a strong contender in RET. However, SMO is very computationally intensive. To mitigate the issue, we adopt a method which has demonstrated in good effectivity and efficiency in illumination source optimization. Based on the gray-level pixel based source representation, the gradient of the cost function is calculated to guide optimization to improve the wafer image fidelity and depth of focus (DOF). Moreover, the similar method has been used in mask optimization to form a complete SMO algorithm. The SMO algorithm is demonstrated using two mask patterns with critical dimension (CD) of 45nm, including a periodic array of contact holes and a tri-bar pattern. Both the results showed high image quality have been achieved using our SMO algorithm.
Mosaic Diamond Pad Conditioners for Improved CMP Performance
Authors: Sung James C. , Tsai Ming-Yi , Pai Yang-Liang , Chou Cheng-Shiang , Chou Chih-Chung , Yang Zongqing , Chen Ying-Tung , Sung Michael
Published: March 2010

A mosaic design of diamond disks that incorporates different cutting characteristics of diamond grits can allow faster polishing of wafers with less pad consumption. Larger diamond grits can make pad asperities with large peak to valley ratios for achieving high polishing rate. On the other hand, Sharp grits can shave the pad effectively as to eliminate the glazed layer. The conventional diamond disks employ similar type of diamond grits across the entire disk. These grits cannot dress and cut the pad with optimization. By combining different types of diamond grits in a cocktail combination, the pad asperities can be controlled to enhance removal rates of the wafer. The glazed layer may also be removed cleaner so wafer defectivity is minimized.
The Pad Dressing Phenomena of Multiple Diamond Grits: Implications for the Design of CMP Pad Conditioners
Authors: Sung James C. , Chen Na-Lin , Pai Yang-Liang , Chou Cheng-Shiang , Chou Chih-Chung , Hu Shao-Chung , Sung Michael
Published: March 2010

Diamond disks are indispensable for dressing CMP pads. However, due to the poor leveling of diamond tips, only a few percents of diamond grits can penetrate the pad. As these few crystals are worn out, the plastic deformation of the pad becomes large relative to the amount of pad is cut. The polishing rate will then decline; and the scratch rate, increase. A novel technique has been developed to identify the cutting tips and their dulling process. The cutting paths become widen and shallow with more and more deformed pad material. Eventually, fewer and fewer scratch lines are present with most touching diamond pushing deformed pad around. Because there are only a handful of diamond grits that are engaged in cutting pad, the number of working crystals can increased substantially by improving the leveling of diamond tips. This improvement can increase the longevity of diamond disks that paves the way for future CMP of 18 inches wafers scheduled to make the debut in 2012.
Novel Diamond Disc Diagnostic Method Based on 'Dry' Coefficient of Friction Measurements
Authors: Sampurno Yasa , Sudargho Fransisca , Meled Anand , Zhuang Yun , Philipossian Ara
Published: March 2010

This paper presents an accurate, consistent and rapid novel method for determining the dry coefficient of friction of conditioner discs. The first part of the study dealt with characterizing 3 diamond discs (i.e. two 'known good' and one 'known bad' diamond discs with the same product number) on top of dry polycarbonate sheets. Results showed that the coefficient of friction of the 'known bad' disc was significantly higher than the two 'known good' discs. As further evidence, primary and secondary vibrational frequency amplitudes from spectral analysis of shear forces showed the 'known bad' disc to have lower average values compared to the two 'known good' discs. The second part of the study had to do with determining whether dry coefficient of friction and total surface area of the furrows generated by the active diamonds on top of dry polycarbonate sheets could be correlated. Results show that coefficient of friction increased with total surface area of the furrows. For diamond disc conditioner manufacturers, this work should provide useful information and rapid disc assessment for improving existing manufacturing processes or for developing new products. The work also underscores the importance of screening diamond conditioner discs before being used in IC manufacturing to improve productivity and COO in CMP modules.
Influence of Surfactant on Improving Cleanliness of Silicon Wafer
Authors: Weiwei Li
Published: March 2010

There are a large number of dangling bonds on Silicon wafer surface during processing, which tend to adsorb substance from surrounding environment to lower their energy. In order to prevent the deposition, adsorption state of pollutants must be controlled in physical adsorption. This paper analyzes the principle about pollutants' adsorption on the silicon wafer surface, and the mechanism of how surfactants to control the particles adsorption state and to prevent re-deposition of particles on the silicon wafer, in addition, gives advices about how to choose the surfactants. It also gets conclusions that composite polyether surfactants could lower the surface tension, enhance the wettability and dispersion of the liquid, effectively improve the space steric between particles and the silicon and prevent the secondary contamination.
The Cleaning of the Surface of Silicon after CMP
Authors: Hu Yi , Liu Yuling , Liu Xiaoyan , Li Yanlei
Published: March 2010

The cleaning of silicon after CMP(chemical mechanical polishing) in ULSI is studied utilizing preferential adsorption knowledge. In the high-speed development of ULSI, the influence of surface quality and rate of production of devices become more and more important.. There are three kinds of adsorption, organic impurity, impurity particles and metal ion on the surface of silicon. The mainly method which is used to clean the surface of the silicon after CMP is double-side scrubbing . Although many companies apply this method to clean the surface ,the method requires that the silicon wafers should be scrubbed and washed in 2h after polishing .The disadvantages are inextricable, for example, high expensive equipment ,low efficiency and etc. In this paper , on the basis of analyzing the adsorption state of the contaminated particles on the surface of the polished silicon wafers ,a non-ion surfactant was chosen which is adsorbed onto the polished silicon wafers.
Characterization of PECVD UV-Transparent Silicon Oxynitride for Passivation of Non-Flash Memory Devices
Authors: Hu Zheng-Jun , Chen Shou-Mian
Published: March 2010

Conventional silicon oxynitride SiON, superior to SiN due to its lower stress and better impervious barrier properties to SiO2, has found only limited application as the passivation layer for non-volatile memory due to its opacity to ultraviolet (UV) light. To tackle this issue, a UV-transparent silicon oxynitride process is developed. A full factorial design of experiment (DOE) is used to study the UV-transmittance of the film from the process parameters. In addition, FT-IR is performed to characterize the Si-O-N bonds, pin-hole test for the film integrity, and varying UV erase time for the corresponding device performance.
Advanced HDP STI Gap-Fill Development in 65nm Logic Device
Authors: Chen Yingjie , Yuan Hongtao , Zhang Z.-Y. , Li Nicola , Chan Diana , Chen James C. , Li Xianyuan , Zhao Ganming
Published: March 2010

High density plasma chemical vapor deposition (HDP-CVD) has been proven to be a sucessful process for shallow trench isolation (STI) gap fill in advanced CMOS device fabrication. As CMOS technology nodes continue to shrink, STI gap-fill requirement become more and more challenging. To keep pace with the stringent requirements, a novel HDP gap-fill process - Integrated Proess Modulation (IPM) has been developed to fill these aggressive structures. IPM process, which is extending from Deposition - Etch - Deposition (DED) process, is made of a serial of deposition/etch cycles, which is one of techniques to keep trench open by using NF3-based plasma dry etch before the trench nearly closed by film deposition. Based on this process model, HDP gap-fill capability has been greatly extended to 65nm and beyond. This paper summarizes the STI gap-fill development and optimization work of IPM processes
Ta(N) Barrier Film Effect on Via RC in Advanced Cu Interconnection
Authors: Liechao Luo , Hu Adrian , Kang Jian , Gong Summer , Cao Zhitao
Published: March 2010

The TaN/Ta stack film is widely used as the barrier layer for Cu interconnection in modern VLSI industry. The correlation between the TaN/Ta barrier layer process and the Via RC is studied in the paper. A model was set up to estimate the Via RC based on bottom Ta thickness on a defined structure. At the same time, two new approaches were developed to optimize the current device process and get the expected results.
Development of ALD HfZrOx with TDEAH, TDEAZ and H2O
Authors: Shi Xiaoping , Tielens Hilde , Takeoka Shinji , Nakabayashi Takashi , Nyns Laura , Adelmann Christoph , Delabie Annelies , Schram Tom , Ragnarsson Lars-Ake , Schaekers Marc , Date Lucien , Schreutelkamp Robert , Van Elshocht Sven
Published: March 2010

A 300mm ALD HfZrOx process using TDEAH, TDEAZ, and H2O is developed. This process applies a nano-laminate approach to grow a HfZrOx film by intermixing ALD HfO2 and ZrO2 around 250{degree sign}C. It is found that the corresponding Zr content of the film, measured by RBS, increases linearly with the cycle ratio of Zr/(Zr+Hf). In addition, the initial growth behavior of the HfZrOx film of this unique process is insensitive to the starting surface condition and eliminates the long incubation as observed for the halide-based ALD processes. The as-deposited HfZrOx films are amorphous, which can be crystallized with a 950{degree sign}C postdeposition anneal. Depending on the film composition, a different crystalline phase is formed ranging from monoclinic to tetragonal with increasing Zr content. CMOS transistors, using HfZrOx as gate dielectric, are fabricated for the evaluation of the corresponding device performance. Device results show that all splits with HfZrOx as gate dielectric yield not only a similar EOTJg performance but also very low leakage, which demonstrate that ALD HfZrOx is a promising candidate for sub-1nm EOT scaling.
A Study of 65nm Silicon Etch
Authors: Zhao Lin-Lin , Huang Yi , Han Bao-Dong , Zhang Hai-Yang , Han Qiu-Hua , Chang Shih-Mou
Published: March 2010

During the process development and mass production of 65nm technology node, the role of silicon etch is essential to meet more stringent device requirements. The control of shallow trench isolation (STI) depth uniformity and poly gate profile necessitate the combination of more advanced silicon etch methodology, in-situ measurement and integration scheme. This paper presents a study of the difficulties and corresponding solutions in 65nm silicon etch from the point view of process development and mass production. In development phase, the STI trench profile and the depth uniformity of STI depth can be well controlled by etch recipe tuning. In mass production phase, we focused on the impact of different products on the inter-field variation of STI depth. Results show a good correlation of depth to pattern density variation. Such relationship has been utilized in feed-forward mode to fulfill the tightening and robust process control. Besides, we also address the influence of oxide amount variation in STI fabrication and STI step height difference on poly gate profile and pits defect.
Synchronous Pulsed Plasma for Silicon Etch Applications
Authors: Darnon Maxime , Petit-Etienne Camille , Pargon Erwine , Cunge Gilles , Vallier Laurent , Bodart Paul , Haas Moritz , Banna Samer , Lill Thorsten , Joubert Olivier
Published: March 2010

This paper investigates the interest of synchronous pulsed plasmas to etch silicon in HBr/O2 chemistries. Using mass spectrometry, ellipsometry and angle resolved X-ray photoelectron spectroscopy, we demonstrate that the radical concentration in the plasma, the etch rate and formation of passivation layers, can be controlled by the RF pulse parameters (frequency and duty cycle). Accordingly, pattern profiles are improved, selectivity to the mask is increased and the silicon recess is reduced from 4 to 0.8 nm when the HBr/O2 plasma lands on thin silicon oxide.
Pattern Density Effect in 65nm Logic BEOL Al-Pad Etch
Authors: Fu Ya-Li , Zhang Hai-Yang , Chang Shih-Mou , Wang Xin-Peng , Sun Wu , Huang Yi , Yin Xiao-Ming , Han Bao-Dong
Published: March 2010

As semiconductor device is being scaled down to 65nm node and below, the control of pattern density effect in back end of line (BEOL) etch becomes more crucial to ensure the on-target production delivery. Pattern density difference normally stems from the specific design of various products. This paper addresses the challenges and solutions to reduce the influence of pattern density variation in 65nm BEOL logic Al-pad etch processes. Challenges include the impact of pattern density on A) corrosion window with different Al-pad photo transmission rates (TR); B) within-wafer profile loading between Al-line (dense feature) and Al-pad (iso feature). Polymer mode has been proven as one of potential mechanisms for these issues. The corresponding feasible solutions focus on A) the adjustment of polymer gas ratio for any product based on its actual pattern density. B) the optimized combo of chemicals and bias power to reduce the within-wafer dense and iso loading.
Thin Wafer Handling Challenges and Emerging Solutions
Authors: Farrens Shari N. , Bisson Peter , Sood Sumant , Hermanowski James
Published: March 2010

Temporary bonding attaches substrates to a carrier so that after thinning to the desired thickness further backside fabrications steps can be conducted with "normal" process flows in standard semiconductor equipment. The selection of a suitable temporary adhesive is key to the success of thin wafer handling. The major requirements of temporary adhesives are related to its process flow, thermal stability, chemical resistance, and mechanical strength. The ideal thermal stability should allow high temperature processing up to 400C for dielectric deposition in high aspect ratio vias, polymer curing, solder reflow, metal sintering, permanent bonding or other high temperature processing. The adhesive must be resistant to the chemicals commonly used after wafer thinning. Mechanical strength is required to hold the thin wafer rigidly during processing, especially during permanent bonding applications otherwise the thinned wafer will flex and prevent bonding. The challenge arises in finding a simultaneous solution to these problems while allowing for the gentle release of the thinned substrate to its final, permanent substrate or package without yield loss or stress. This paper will highlight some of the more recent solutions for thin wafer handling that have emerged through technology innovation.
3D IC Designs: Myth vs. Reality
Authors: Tang Jing Jou , Wu Jan Liang
Published: March 2010

Through Silicon Via (TSV) is an emerging technology for 3D integration. The design flow, supply chain, and infrastructure of semiconductor industry will be reconstructed because of this technique. Using this technique, the path to "More-than-Moore" era seems to be smooth and promising. However In this paper, we try to give our reflective judgment to this hottest topic. 4 basic myths will be inspected and contradicted based on experimental and statistic data we observed. In this paper, we will discuss about the myths including the arguments on the issues of necessity, length, parasitic value, and EDA tools for TSVs.
Packaging Challenges on Shrink Chip Technology
Authors: Yang Xiao , Soh Yuen Chun , Wu Huiliang
Published: March 2010

As technology grows, semiconductor industry evolved towards tinier & thinner packages to meet market demand. To create competitiveness, chip size shrinkage at front-end wafer fabrication is essential for newer packages technology. With the tireless effort from front-end fab, die size & thickness are reduced up to 30%. There are changes on wire bond pad as well, pad opening is reduced & pad metallization is changed to NiPPdAu with barrier metal underneath. This paper will discuss in details mainly on die bonding & wire bonding challenges for shrink chip technology. Critical defects such as vertical crack die, die surface contamination & passivation crack were observed during process development stage. Several efforts were made to address them accordingly. Finally this paper will share on new failure mechanism observed during ramp up, evaluations for risk assessment & future improvement ideas to overcome mass production obstacles.
Large Graphite Films Exolved from Molten Metal Catalyst
Authors: Chang Kuen-Liang , Hsu Kai-Hung , Hu Shao-Chung , Lin I-Chiao , Yu Chien-Pei , Sung Michael , Sung James C.
Published: March 2010

Graphene is the ideal material for many dream applications, such as single electron transistors, field emission sources, light through electrodes, flexible solar cells, wall paper displays, UV light emitting diodes, atomic gas sensors, DNA or antigen wafers, terra hertz surface acoustic wave (SAW) generators and filters...etc. However, a practical method to fabricate meter-sized graphene is still beyond imagination. In this research, we reported a simple technology to harvest large area graphite films by using molten alloy as the catalyst. Each film contains hundreds or thousands layers of graphene. Some stacks of graphene revealed silk-like tenderness with transparent folding lines. This liquid phase epitaxy (LPE) process appears scalable for making graphene layers measured in meter size. This paper also presented many intriguing aspects related to the growth of large graphene.
Selective Epitaxial Growth of InP in STI Trenches on Off-Axis Si (001) Substrates
Authors: Wang Gang , Nguyen Duy , Leys Maarten , Loo Roger , Brammertz Guy , Richard Olivier , Bender Hugo , Dekoster Johan , Meuris Marc , Heyns Marc , Caymax Matty
Published: March 2010

We report high quality InP layers selectively grown in shallow trench isolation structures on 6 degree offcut Si (001) substrates capped with a thin Ge buffer layer. The Ge layer was used to reduce the thermal budget for surface clean and double step formation. The atomic steps on the Ge surface were recovered after a bake at 680°C. Smooth nucleation layer was obtained at 420°C on the Ge surface. Baking the Ge surface in As ambient facilitates the InP nulceation and improves the InP crystalline quality. This improvement is attributed to the effective As adsorption on the Ge surface and the polar Ge:As surface prevents the islanding of InP seed layer. Stacking faults were found in the InP layers as a result of threading dislocation dissociation and high quality InP layers were obtained in trenches with aspect ratio greater than 2.
Amorphous Diamond Solar Cells with Nanodiamond Quantum Wells
Authors: Sung James C. , Kan Ming-Chi , Sung Michael
Published: March 2010

Thin film solar cells have emerged in recent years, in particular, those made of amorphous silicon or CIGS (copper indium gallium sellenide). By tendon of boron doped amorphous diamond with phosphorus doped amorphous silicon, the conversion efficiency may rival that of crystalline silicon. On the other hand, the CdS top layer for CIGS is not only poisonous, but also UV degradable. Amorphous diamond coating with N doping can replace CdS to boost CIGS's efficiency also. Nanodiamond may be sputtered from diamond grit or diamond film as target. The PVD formed nanodiamond layer can be located at the interface between P and N types. In this case, the quantum well effect can allow the production of multiple electrons per incident photon. In addition, the output voltage may be increased due to the wide band gap of nanodiamond.
Best in Class Polysilicon Technology
Authors: Hamilton John R. , Rami Anand C.
Published: March 2010

With the increasing cost and environmental impact of fossil fuels, the generation of power from renewable energy sources will continue its dramatic rise. Best in Class technologies for the production of polysilicon will assure that solar energy continues its rapid increase in the share of renewable energy sources. The latest developments with the commercially viable chlorosilane-based polysilicon manufacturing processes are discussed. Best in class definitions of safe and reliable production resulting in the highest quality and lowest cash cost are used to define an overall approach to the evaluation of available technologies.
Modeling of the 3D Unsteady Melt Flow in an Industrial-Scale Cz-Si Crystal Growth Using LES Method
Authors: Liu Xin , Liu Lijun , Wang Yuan , Kakimoto Koichi
Published: March 2010

We present a computational model for the 3D unsteady turbulent melt flow in an industrial-scale Cz-Si growth basing on the Large Eddy Simulation (LES) method in curvilinear grids. The filtered governing equations were solved basing on the finite-volume method for non-orthogonal grids. The turbulent transport of momentum and heat in the melt was investigated. The first and the second order statistics quantities of velocity and temperature fields were computed for analysis of the turbulent fluctuation in the melt flow. The effects of crystal and crucible rotation, thermal buoyancy and thermo-capillary on the melt flow were studied comprehensively through analysis of the instantaneous and mean velocity fields. The turbulent nature consisted of the unsteady and three-dimensional behavior of the melt flow was verified. Temperature fluctuations are obviously observed close to the crystallization zone.
Wet Etching Technology for Semiconductor and Solar Silicon Manufacturing: Part 2 - Process, Equipment and Implementation
Authors: Erk Henry F.
Published: March 2010

Wet etching is an important step in the manufacturing of semiconductor and solar wafers and for the production of MEMS devices. While it has been replaced by the more precise dry etching technology in advanced semiconductor device fabrication, it still plays an important role in the manufacture of the silicon substrate itself. It is also used for providing stress relief and surface texturing of solar wafers in high volume. The technology of wet etching silicon for semiconductor and solar applications will be reviewed. Impact on this step for wafer properties and critical parameters (flatness, topology and surface roughness for semiconductor wafers, surface texture and reflectance for solar wafers) will be presented. The rationale for the use of a etching technology and etchant for specific applications in semiconductor and solar wafer manufacturing will be presented.
Polishing of Semiconductor Materials
Authors: Rhoades Robert L.
Published: March 2010

Polishing has been the critical final step in prime wafer manufacturing since the beginning of the semiconductor IC industry nearly fifty years ago. Chemical mechanical planarization (CMP) is a very different type of polishing developed roughly twenty years ago for planarization and removal of thin films during device fabrication. A simplified comparison of the two processes is presented, including their respective consumables and equipment. As new applications are developed, both types of polishing must continue to evolve and adapt to changing requirements.
The Optimization Aspect of Screen Printed Si Solar Cell
Authors: Shahrul Anizan W. , Cheow Siu Leong , Khairy M.Y. , Salwa Abdul Ghani Nurul , Amin Nowshad , Sopian Kamaruzzaman
Published: March 2010

The unpredictable fossil fuel price makes the dependant of the usage of the petroleum to produce energy need to be reduced. Solar cells are used to capture the photons which generate the energy. This is the alternative way to generate energy. However the efficiency of the cells to turn the amount of photon to electricity needs to be high and so the cells enhancement is needed. This involved the whole process of the developing of the cells. Only Si solar cells will be discussed and optimizing this kind of cell will focus at the back end process which involve after the texturing process. The process involved would be metal contact screen printing and metal paste co-firing.
A Research on Thick PIN Detector with High Breakdown Voltage
Authors: Wu Dongmei , Yu Min , Ma Shenglin , Zhang Lu , Wei Chunxi , Zhang Xiaohang , Li Qiang , Li Guanhuang , Wang Haomin , Wang Jinyan , Jin Yufeng
Published: March 2010

The Thick PIN detector fabricated on high resistivity silicon is widely applied for high energy particle detection. In this work, the structure of detector is investigated and optimized to achieve high breakdown voltage, which is necessary to deplete the detector. Structures of field plate and guard ring are investigated. The effects of field plate width and distance to guard ring are investigated by simulation to optimize the device structure. The analysis on the electric field distribution within the detector is performed. The silicon wafer with high resistivity is applied in the experiments. Devices are fabricated for breakdown voltage research. It is shown that with the structure of field plate and guard ring, the breakdown voltage of device on high resistivity silicon can be increased effectively. The optimized structure of detector is presented. The thick PIN detector with thickness of 1.5mm is fabricated and tested.
Gene expression in hypothalamus, liver, and adipose tissues and food intake response to melanocortin-4 receptor agonist in pigs expressing melanocortin-4 receptor mutations
Authors: Barb C. Richard , Hausman Gary J. , Rekaya Romdhane , Lents Clay A. , Lkhagvadorj Sender , Qu L. , Cai W. , Couture Oliver P. , Anderson Lloyd L. , Dekkers Jack C. M. , Tuggle Christopher K.
Published: March 2010

Transcriptional profiling was used to identify genes and pathways that responded to intracerebroventricular injection of melanocortin-4 receptor (MC4R) agonist [Nle4, d-Phe7]-α-melanocyte stimulating hormone (NDP-MSH) in pigs homozygous for the missense mutation in the MC4R, D298 allele ( n = 12), N298 allele ( n = 12), or heterozygous ( n = 12). Food intake (FI) was measured at 12 and 24 h after treatment. All pigs were killed at 24 h after treatment, and hypothalamus, liver, and back-fat tissue was collected. NDP-MSH suppressed ( P < 0.004) FI at 12 and 24 h in all animals after treatment. In response to NDP-MSH, 278 genes in hypothalamus ( q ≤ 0.07, P ≤ 0.001), 249 genes in liver ( q ≤ 0.07, P ≤ 0.001), and 5,066 genes in fat ( q ≤ 0.07, P ≤ 0.015) were differentially expressed. Pathway analysis of NDP-MSH-induced differentially expressed genes indicated that genes involved in cell communication, nucleotide metabolism, and signal transduction were prominently downregulated in the hypothalamus. In both liver and adipose tissue, energy-intensive biosynthetic and catabolic processes were downregulated in response to NDP-MSH. This included genes encoding for biosynthetic pathways such as steroid and lipid biosynthesis, fatty acid synthesis, and amino acid synthesis. Genes involved in direct energy-generating processes, such as oxidative phosphorylation, electron transport, and ATP synthesis, were upregulated, whereas TCA-associated genes were prominently downregulated in NDP-MSH-treated pigs. Our data also indicate a metabolic switch toward energy conservation since genes involved in energy-intensive biosynthetic and catabolic processes were downregulated in NDP-MSH-treated pigs.
Long-Term Survival and PSA Control with Radiation and Immunotherapy for Node Positive Prostate Cancer
Authors: Kamrava M. , Tsang Kwong Y. , Madan R. A. , Kaushal A. , Coleman C. N. , Gulley J.
Published: March 2010

We describe a patient with node positive prostate cancer treated with radiation, androgen deprivation, and immunotherapy with long-term overall survival and PSA control. ELISPOT immunoassay studies demonstrated PSA specific T-cells prior to starting vaccine therapy suggesting that this positive response may be related to an improved antitumor immune response of the patient, increased immunogenicity of the tumor, or decreased activation of immune escape pathways. Further evaluation of therapeutic cancer vaccines in combination with radiation and hormonal therapy in the definitive management of prostate cancer is warranted.
Transcriptomic Analysis of Starch Biosynthesis in the Developing Grain of Hexaploid Wheat
Authors: Stamova Boryana S. , Laudencia-Chingcuanco Debbie , Beckles Diane M.
Published: March 2010

The expression of genes involved in starch synthesis in wheat was analyzed together with the accumulation profiles of soluble sugars, starch, protein, and starch granule distribution in developing caryopses obtained from the same biological materials used for profiling of gene expression using DNA microarrays. Multiple expression patterns were detected for the different starch biosynthetic gene isoforms, suggesting their relative importance through caryopsis development. Members of the ADP‐glucose pyrophosphorylase, starch synthase, starch branching enzyme, and sucrose synthase gene families showed different expression profiles; expression of some members of these gene families coincided with a period of high accumulation of starch while others did not. A biphasic pattern was observed in the rates of starch and protein accumulation which paralleled changes in global gene expression. Metabolic and regulatory genes that show a pattern of expression similar to starch accumulation and granule size distribution were identified, suggesting their coinvolvement in these biological processes.
Phenotypic and Genotypic Antimicrobial Resistance Profiles ofCampylobacter jejuniIsolated from Cattle, Sheep, and Free-Range Poultry Faeces
Authors: Oporto Beatriz , Juste Ramón A. , Hurtado Ana
Published: March 2010

Minimum inhibitory concentrations (MIC) of 13 antimicrobial agents were determined by broth microdilution for 72Campylobacter jejunistrains from livestock. Twenty-three (31.9%) isolates were fully susceptible; all isolates were susceptible to erythromycin, chloramphenicol, streptomycin, gentamicin, sulfamethoxazole, and meropenem, and all but one to kanamycin. Resistance to quinolones was highest (52.8%), reaching similar values among poultry, dairy cattle, and sheep, but lower in beef cattle. Resistance to tetracyclines (48.6%) was mainly associated to dairy cattle andβ-lactams (26.4%) to poultry. Multidrug resistance was mainly detected in dairy cattle (28.6%) and poultry (21.0%), whereas beef cattle had the highest percentage of fully susceptible isolates. Two real-time PCR assays to detect point mutations associated to quinolone (C257T in thegyrA gene) and macrolide (A2075G in the 23S rRNA genes) resistance were developed and validated on these strains. The analysis of a further set of 88 isolates by real-time PCR confirmed the absence of macrolide resistance and demonstrated the reproducibility and processability of the assay.
Calculation of Rail Internal Impedance by Using Finite Elements Methods and Complex Magnetic Permeability
Authors: Dolara Alberto , Leva Sonia
Published: March 2010

The internal parameter of UNI 60 rail is calculated by using finite elements methods. Steel's characterizations by its normal magnetization curve and by complex magnetic permeability are here considered and included into the proposed FEM models. Rail's resistance and internal inductance in function of current and frequency are calculated using both FEM and analytical models. The results obtained at the frequency of 50 Hz are compared with few measurements available, and then they are extended to other frequencies.
Exact Solutions and Localized Structures for Higher‐Dimensional Burgers Systems
Authors: Peng Yan-ze
Published: March 2010

A (2 + 1) dimensional Burgers equation and a coupled higher dimensional Burgers system is studied by the singular manifold method. The Bäcklund transformations are obtained. Some interesting exact solutions are given. Then localized structures, such as dromion and solitoff, are found, and their interaction properties are numerically studied. The fusion phenomena of two dromions, a dromion and a solitoff, are for the first time reported.
Analysis of Pollen Collected byAndrena flavipesPanzer (Hymenoptera: Andrenidae) in Sweet Cherry Orchards, Afyonkarahisar Province of Turkey
Authors: Güler Yasemin , Sorkun Kadriye
Published: March 2010

Andrena, which is the largest genus in the Andrenidae, is a very important genus for the pollination of fruit trees.Andrena flavipesPanzer is one of the most common species observed in the study area and can continue the flight activity even under low temperature. In this study, the pollen collected byA. flavipeswas determined. In addition, the potential to carry sweet cherry pollen of the aforementioned species was also researched. For the pollen preparates, the scopae of 34 females were used. As a result of the diagnosis studies, it was determined thatA. flavipesspecies collected the pollens of 13 families and that the dominant pollen group belonged to the Brassicaceae. It was ascertained thatA. flavipescollected sweet cherry pollen and that the sweet cherry flowers do not represent a primary pollen source, however.
Fixed Point Results for Multivalued Maps in Metric Spaces with Generalized Inwardness Conditions
Authors: Frigon M
Published: March 2010

We establish fixed point theorems for multivalued mappings defined on a closed subset of a complete metric space. We generalize Lim's result on weakly inward contractions in a Banach space. We also generalize recent results of Azé and Corvellec, Maciejewski, and Uderzo for contractions and directional contractions. Finally, we present local fixed point theorems and continuation principles for generalized inward contractions.
The Dual Role of Zonula Occludens (ZO) Proteins
Authors: Bauer H. , Zweimueller-Mayer J. , Steinbacher P. , Lametschwandtner A. , Bauer H. C.
Published: March 2010

ZO (zonula occludens) proteins are scaffolding proteins providing the structural basis for the assembly of multiprotein complexes at the cytoplasmic surface of intercellular junctions. In addition, they provide a link between the integral membrane proteins and the filamentous cytoskeleton. ZO proteins belong to the large family of membrane-associated guanylate kinase (MAGUK)-like proteins comprising a number of subfamilies based on domain content and sequence similarity. Besides their structural function at cell-cell contacts, ZO proteins appear to participate in the regulation of cell growth and proliferation. Detailed molecular studies have shown that ZO proteins exhibit conserved functional nuclear localization and nuclear export motifs within their amino acid sequence. Further, ZO proteins interact with dual residency proteins localizing to the plasma membrane and the nucleus. Although the nuclear targeting of ZO proteins has well been described, many questions concerning the biological significance of this process have remained open. This review focuses on the dual role of ZO proteins, being indispensable structural components at the junctional site and functioning in signal transduction pathways related to gene expression and cell behavior.
The Role of Exercise-Induced Myokines in Muscle Homeostasis and the Defense against Chronic Diseases
Authors: Brandt Claus , Pedersen Bente K.
Published: March 2010

Chronic inflammation is involved in the pathogenesis of insulin resistance, atherosclerosis, neurodegeneration, and tumour growth. Regular exercise offers protection against type 2 diabetes, cardiovascular diseases, colon cancer, breast cancer, and dementia. Evidence suggests that the protective effect of exercise may to some extent be ascribed to the antiinflammatory effect of regular exercise. Here we suggest that exercise may exert its anti-inflammatory effect via a reduction in visceral fat mass and/or by induction of an anti-inflammatory environment with each bout of exercise. According to our theory, such effects may in part be mediated via muscle-derived peptides, so-called “myokines”. Contracting skeletal muscles release myokines with endocrine effects, mediating direct anti-inflammatory effects, and/or specific effects on visceral fat. Other myokines work locally within the muscle and exert their effects on signalling pathways involved in fat oxidation and glucose uptake. By mediating anti-inflammatory effects in the muscle itself, myokines may also counteract TNF-driven insulin resistance. In conclusion, exercise-induced myokines appear to be involved in mediating both systemic as well as local anti-inflammatory effects.
Regulation of P-Glycoprotein in Renal Proximal Tubule Epithelial Cells by LPS and TNF-α
Authors: Heemskerk Suzanne , Peters Janny G. P. , Louisse Jochem , Sagar Seil , Russel Frans G. M. , Masereeuw Rosalinde
Published: March 2010

During endotoxemia, the ATP-dependent drug efflux pump P-glycoprotein (Abcb1/P-gp) is upregulated in kidney proximal tubule epithelial cells. The signaling pathway through which lipopolysaccharide (LPS) or tumor necrosis factor-α(TNF-α) regulates P-gp expression and activity was investigated further in the present study. Exposure of rat kidney proximal tubule cells to TNF-αalone or TNF-αand LPS increased P-gp gene and protein expression levels and efflux activity, suggesting de novo P-gp synthesis. Upon exposure to TNF-αin combination with LPS, P-gp activity in renal proximal tubule cells is increased under influence of nitric oxide (NO) produced by inducible NO synthase. Upon exposure to TNF-αalone, P-gp upregulation seems to involve TLR4 activation and nuclear factor kappaB (NF-κB) translocation, a pathway that is likely independent of NO. These findings indicate that at least two pathways regulate P-gp expression in the kidney during endotoxemia.
Rapidly Evolving Giant Dermatofibroma
Authors: Lang K. J. , Lidder S. , Hofer M. , Graham C. , Taylor A.
Published: March 2010

Dermatofibroma, also known as “fibrous histiocytoma”, is a benign dermal or subcutaneous poorly circumscribed proliferation of spindle-shaped fibroblasts and macrophages in the dermis. Although it is commonly present as a brownish nodule the legs of females, it may also arise on the upper extremities, trunk, and rarely on the head. The exact pathogenesis is unclear. However, it is widely believed that the originating insult to the dermis is a folliculitis, an arthropod bite, or an unspecified initial inflammatory condition. Giant dermatofibromas of greater than 5 cm in diameter are rare, with only 22 cases reported in the literature. We present a case of a rapidly evolving pedunculated mass in the groin of a male patient. Histological examination confirmed this to be a giant dermatofibroma. Though this specimen cannot is not confirmed as such, the cellular subtype is sometimes present as a larger lesion with anecdotal reports of local recurrence and distant metastases. The clinical and radiological features which were somewhat suspicious of malignancy are considered in the context of the definitive pathological diagnosis of a benign lesion.
Casing Pipe Damage Detection with Optical Fiber Sensors: A Case Study in Oil Well Constructions
Authors: Zhou Zhi , He Jianping , Huang Minghua , He Jun , Chen Genda
Published: March 2010

Casing pipes in oil well constructions may suddenly buckle inward as their inside and outside hydrostatic pressure difference increases. For the safety of construction workers and the steady development of oil industries, it is critically important to measure the stress state of a casing pipe. This study develops a rugged, real-time monitoring, and warning system that combines the distributed Brillouin Scattering Time Domain Reflectometry (BOTDR) and the discrete fiber Bragg grating (FBG) measurement. The BOTDR optical fiber sensors were embedded with no optical fiber splice joints in a fiber-reinforced polymer (FRP) rebar and the FBG sensors were wrapped in epoxy resins and glass clothes, both installed during the segmental construction of casing pipes. In situ tests indicate that the proposed sensing system and installation technique can survive the downhole driving process of casing pipes, withstand a harsh service environment, and remain intact with the casing pipes for compatible strain measurements. The relative error of the measured strains between the distributed and discrete sensors is less than 12%. The FBG sensors successfully measured the maximum horizontal principal stress with a relative error of 6.7% in comparison with a cross multipole array acoustic instrument.
Shift Work, Jet Lag, and Female Reproduction
Authors: Mahoney Megan M.
Published: March 2010

Circadian rhythms and “clock gene” expression are involved in successful reproductive cycles, mating, and pregnancy. Alterations or disruptions of biological rhythms, as commonly occurs in shift work, jet lag, sleep deprivation, or clock gene knock out models, are linked to significant disruptions in reproductive function. These impairments include altered hormonal secretion patterns, reduced conception rates, increased miscarriage rates and an increased risk of breast cancer. Female health may be particularly susceptible to the impact of desynchronizing work schedules as perturbed hormonal rhythms can further influence the expression patterns of clock genes. Estrogen modifies clock gene expression in the uterus, ovaries, and suprachiasmatic nucleus, the site of the primary circadian clock mechanism. Further work investigating clock genes, light exposure, ovarian hormones, and reproductive function will be critical for indentifying how these factors interact to impact health and susceptibility to disease.