bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manufacturable 300mm Wafer Thinning for 3D Interconnect Applications
Authors: Qureshi Jamal , Caramto Raymond , Olson Stephen , Mase Jerry , Ito Toshihiro , Yamamoto Eiichi 
Published: August 2010

Abstract3D interconnect wafer-to-wafer or die-to-wafer integration requires a wafer thinning operation to expose copper (Cu)-filled through-silicon vias (TSVs) from the backside of the wafer. The wafer thinning flow uses edge trim, backgrind, backpolish, and chemical mechanical polishing (CMP). This paper presents an overview of the wafer grinding process. We have demonstrated the capability to edge-trim and backgrind 300 mm TSV and non-TSV wafers down to 30 microns (μm) while bonded to a handle wafer. TSV wafers were further processed on a CMP tool to remove the last few microns of Si, exposing the Cu-filled TSVs. Metrology techniques were used to inspect and measure the wafer edge trim and final thinned wafer thickness. The quality of the thinned wafer was characterized by atomic force microscopy (AFM) to observe surface roughness and by transmission electron microscopy (TEM) to quantify crystalline damage below the surface of the thinned wafer. Further characterization included measuring wafer thickness, total thickness variation (TTV), bow, and warp. Exposed TSVs were characterized by laser microscope to measure the height of Cu protrusions. These critical elements of a manufacturing-worthy 300 mm wafer thinning process for 3D are discussed.
Design, Characteristics and Performance of Diamond Pad Conditioners
Authors: Pysher Douglas J. , Goers Brian , Zabasajja John 
Published: August 2010

AbstractA wide range of diamond pad conditioner (disk) designs have been characterized and key performance metrics have been collected. Relationships between design characteristics including diamond size and shape, spatial density, and tip height distribution and polishing pad wear rates and pad surface textures have been established for a variety of pads.Estimation of the depth-of-penetration of working diamonds, from used disk analyses, allows meaningful topographic assessments of alternative conditioner designs and predictions of relative performance. An example of an improved conditioner that illustrates this design methodology is given.Conditioner aggressiveness and its decay in various slurries have been measured to assess disk lifetime in Chemical Mechanical Planarization (CMP) processes environments. Key factors affecting disk lifetime are discussed and an improved-lifetime conditioner for use in aggressive slurries will be reviewed.
Characterization of Large Particles in Fumed Silica Based CMP Slurry
Authors: Rader W. Scott , Holt Timothy , Tamai Kazusei 
Published: August 2010

AbstractLarge particles in fumed silica dispersions were characterized by sedimentation, light scattering techniques, Transmission Electron Microscopy (TEM), and lacunarity. Applying centrifugation to fumed silica dispersions generated differences in sedimentation rates of large particles. The sedimentation rates of the large particles were affected by morphological differences and the particles remaining in the supernatant displayed buoyant behavior. The large particle morphology varied from branch like aggregates containing large primary particles to particles comprised of highly coalesced, tightly packed small primary particles. The results indicate the presence of different types of large particles in fumed silica dispersions to which conventional large particle characterization is unable to distinguish.
C2H4-Based Plasma-Assisted CD Shrink and Contact Patterning for RRAM Application
Authors: Milenin Alexey , Lisoni Judit , Jossart Nico , Jurczak Malgorzata , Struyf Herbert , Shamiryan Denis , Brouri Mohand , Boullart Werner 
Published: August 2010

AbstractCritical dimension (CD) shrink and patterning of contact features via plasma etching were studied for typical resistive random access memory (RRAM) stacks. These consist of SiO2 and Si3N4 (total thickness of 65 80 nm) with NiO or pure Ni at the bottom. First, the contact patterning of RRAM stacks was investigated for 90 nm contacts. Thus, a standard high power contact etch recipe was shown to give rise to resist strip challenges due to the incorporation of sputtered Ni in the resist film. Therefore, a low-sputter-yield contact etch recipe based on a CF4/H2/Ar gas chemistry was introduced. The ion sputter efficiency of the recipe was estimated from a blanket SiO2 sputter-yield experiment in Ar plasma for the same recipe settings: this yielded values close to the Ni sputter-yield threshold. Second, plasma-assisted CD shrink was studied in combination with the newly developed patterning scheme to get the contact CD well below the initial 90-nm litho print size. It was shown that a low contact etch power regime could also provide a larger window for contact CD shrink using a C2H4-based chemistry: e.g. the demonstrated CD shrink from 90 nm down to sub-40 nm was shown to be extremely challenging in the case of a high power regime due to polymer instability enhanced with the resulting thickness increase. Perhaps, the relaxation of the polymer film stress, which was measured to be in the range of 1200-1500 MPa, is more easily triggered at higher power settings, which leads to polymer blistering. Finally, the optimization of the plasma-assisted CD shrink step in combination with the low-sputter-yield contact etch recipe was demonstrated to be able to provide CDs as small as 27 nm. The demonstrated approach shows that plasma-assisted CD shrink can provide a robust test vehicle for research programs that require the patterning of small features in the sub-40-nm CD range.
Barrier Metal Ions Drift into Porous Low k Dielectrics under Bias-Temperature stress
Authors: He Ming , Ou Ya , Wang Pei-I , Vanamurthy Lakshmanan H , Bakhru Hassaram , Lu Toh-Ming 
Published: August 2010

AbstractTa family has been used as barrier to prevent Cu diffusion into interlayer dielectric in IC applications. Recent experiments demonstrated a more severe flatband voltage shift (ΔVFB) occurred for Ta/porous low k dielectrics/Si capacitors compared to that of Cu/porous low k dielectrics/Si capacitors after a moderate bias temperature stress (BTS). The flatband voltage shift under BTS was interpreted as the penetration of Ta ions into porous low k dielectrics. However, this interpretation has been under debate. In this paper, by using Secondary Ion Mass Spectrometry (SIMS) backside sputter depth profile technique, we report a direct evidence of Ta ions inside porous methyl silsesquioxane (MSQ) in a Ta/MSQ/Si structure after BTS.
An Optimized 300mm BCB Wafer Bonding Process for 3D Integration
Authors: Singh Pratibha , Hudnall John , Qureshi Jamal , Kamineni Vimal Kumar , Taylor Chris , Rudack Andy , Diebold Alain , Arkalgud Sitaram 
Published: August 2010

AbstractWafer bonding using benzocyclobutene (BCB) has been discussed in the past for three-dimensional (3D) integration. This paper reports the development and characterization of a manufacturable BCB bonding process for 300 mm wafers using standard 300 mm tools. A systematic optimization approach has been developed to characterize the bulk properties of the BCB film that can be applied to various integration schemes. We specifically discuss one such application—handle wafer bonding. BCB bonding for a range of cross-linking levels has been investigated. The cross-linking level of BCB before bonding is determined using an infrared (IR) variable angle spectroscopic ellipsometer (VASE) technique. The impact of the BCB film preparation and bonding condition on bond quality is characterized using scanning acoustic microscopy (SAM) , IR microscopy, a razor blade test, and four-point bend methods. Based on the results, an optimum cross-linking level for BCB film before bonding was determined for 300 mm wafers to obtain void-free and dendrite-free bonds. Wafers bonded using the optimized BCB process conditions have successfully sustained backgrinding, dry thinning, and standard BEOL metallization steps.
Structural, Magnetic and Magneto-tranport Properties of Reactive-sputtered Fe3O4 Thin Films
Authors: Wang Xinghua , Goolaup Sarjoosing , Ren Peng , Lew Wen Siang 
Published: August 2010

AbstractThin films of magnetite (Fe3O4) are grown on a single-crystal Si/SiO2 (100) substrate with native oxide using DC reactive sputtering technique at room tempreture (RT) and 300C. The x-ray diffraction(XRD) result shows the thermal energy during deposition enhances the crystallization of the Fe3O4 and x-ray photoelectron spectroscopy confirms the film deposited at 300C is single-phase Fe3O4 while the film deposited at RT is mostly ν-Fe2O3. The electrical measurements show that the resistivity of the Fe3O4 film increases exponentially with decreasing temperature, and exhibit a sharp metal-insulator transition at around 100 K, indicating the Verwey transition feature. The saturation magnetization Ms of Fe3O4 film measured by vibrating sample measurement (VSM) at RT was found to be 445 emu/cm3.
Direct Synthesis of L10-Phase Nanostructured CoPt Using Dense Plasma Focus Device Operating in Non-optimized Focus Mode
Authors: Pan Zhenying , Rawat Rajdeep Singh , Lin Jiaji , Karamat Shumaila , Lee Paul Choon Keat , Springham Stuart Victor , Tan Augustine Tuck Lee 
Published: August 2010

AbstractA direct synthesis of (001) oriented nanostructured CoPt thin films has been successfully achieved using a 880 J pulsed Dense Plasma Focus (DPF) device operating in a non-optimized focus mode with a low charging voltage of about 8 kV. The (001) oriented fct structured L10 phase nanostructured CoPt thin films have been synthesized directly in as-deposited sample, as verified by XRD results, without any post deposition annealing. The SEM imaging results show that nanostructured CoPt were achieved in non-optimized focus mode with agglomerate/particle size ranging from 10 to 55 nm. Furthermore, the VSM analysis shows that the as-deposited samples in non-optimized focus mode have higher coercivity (due to direct L10 phase) as compared the annealed sample and the as-deposited sample of optimized focus mode operation.
Memory Effect in Simple Cu Nanogap Junction
Authors: Suga Hiroshi , Horikawa Masayo , Miyazak Hisao , Odaka Shunsuke , Tsukagoshi Kazuhito , Shimizu Tetsuo , Naitoh Yasuhisa 
Published: August 2010

AbstractWe have investigated the resistance switching effect in Cu nanogap junction. Nanogap structures were created by means of electromigration and their electrical properties were measured in a high vacuum chamber. The measured current-voltage characteristics exhibited a clear negative resistance and memory effect with a large on-off ratio of over 105. The estimation from I-V curves indicates that the resistance switching was caused by the gap size change, which implies that the nanogap switching (NGS) effect also occurs in Cu electrodes, a popular wiring material in an integrated circuit.
Crystallization behavior of Ge1Cu2Te3 amorphous film
Authors: Sutou Yuji , Kamada Toshiya , Saito Yuta , Sumiya Masashi , Koike Junichi 
Published: August 2010

AbstractThe electrical resistance on the crystallization process of sputtered-deposited Ge1Cu2Te3 film was investigated by two-point probe method. It was found that the amorphous Ge1Cu2Te3 film crystallizes into a single Ge1Cu2Te3 phase with a chalcopyrite structure, which leads to a large resistance drop. The crystallization temperature of the Ge1Cu2Te3 amorphous film was about 250 °C, which is about 70 °C higher than the conventional Ge2Sb2Te5 amorphous film. The activation energy for the crystallization of the Ge1Cu2Te3 amorphous film was higher than that of the Ge2Sb2Te5 amorphous film. The Ge1Cu2Te3 compound with a low melting point can be expected to be suitable as the phase change material for PCRAM.
Tuneable CMOS and Current Mirror Circuit with Double-gate Screen Grid Field Effect Transistors
Authors: Shadrokh Yasaman , Fobelets Kristel , Velazquez-Perez Enrique 
Published: August 2010

AbstractThe multiple-gate aspect of the Screen Grid Field Effect Transistor (SGrFET) increases functionality and reduces component count of circuits. An independently-driven gate SGrFET is used to control the switching voltage as well as the gain factor of an inverter. The multi-gate configuration of the SGrFET allows a decrease in output conductance without an increase of transistors count. This leads to a reduction in fabrication complexity, chip area and parasitics. In addition, a simple SGrFETs-based current mirror circuit is proposed with gain factor control.
Tuning the Magnetic Domain Structure of Spin-polarized Complex Oxide Nanostructures
Authors: Bettinger Joanna Strongson , Chopdekar Rajesh V. , Mesler Brooke , Chain Douglas , Doran Andrew , Anderson Erik , Scholl Andreas , Suzuki Yuri 
Published: August 2010

AbstractTo successfully incorporate the highly spin-polarized material La0.7Sr0.3MnO3 (LSMO) into spin-based electronic devices it is essential to be able to control and tune the magnetic domain structure. In this work, we geometrically confine epitaxial thin films of LSMO into hexagons to examine the effect of magnetostatic and magnetic anisotropy energies on the domain formation. We find through careful choice of hexagon aspect ratio, crystalline direction, and substrate orientation, we can tune the magnetic domain formation to be single, two, six (flux closure), or other domain configurations.
Synthesis and Thermal Stability of HfO2 Nanoparticles
Authors: Chaubey Girija Shankar , Yao Yuan , Makongo Mangan Julien Pierre Amelie , Sahoo Pranati , Poudeu Pierre F. P. , Wiley John 
Published: August 2010

AbstractA simple method is reported for the synthesis of monodispersed HfO2 nanoparticles by the ammonia catalyzed hydrolysis and condensation of hafnium (IV) tert-butoxide in the presence of surfactants at room temperature. Transmission electron microscopy shows faceted nanoparticles with an average diameter of 3-4 nm. As-synthesized nanoparticles are amorphous in nature and crystallize upon moderate heat treatment. The HfO2 nanoparticles have a narrow size distribution, large specific surface area and good thermal stability. Specific surface area was about 239 m2/g on as-prepared nanoparticle samples while those annealed at 500 °C have specific surface area of 221 m2/g indicating that there was no significant increase in particle size. This result was further confirmed by TEM images of nanoparticles annealed at 300 °C and 500 °C. X-ray diffraction studies of the crystallized nanoparticles revealed that HfO2 nanoparticles were monoclinic in structure. The synthetic procedure used in this work can be readily modified for large scale production of monodispersed HfO2 nanoparticles.
Emission Inhomogeneity in InAs Quantum Dot DWELL Structures
Authors: Vivas Hernández Alejandro , Polupan Gerorgiy , Velazquez Eric , Guerrero Moreno Ingri J. , Scherbyna L. 
Published: August 2010

AbstractThe photoluminescence spectra and its homogeneity for InAs quantum dots (QDs) embedded into In0.15Ga0.85As/GaAs quantum well (QW) structures with QDs grown at different temperatures (470-535°C) have been investigated at 300 K. Photoluminescence (PL) spectra along the scanning line crossed the wafers were measured at 300 K in a set of points on the QD structures under the excitation of the 804 nm line of a solid state IR laser at an excitation power density of 100 W/cm2. In QD structures with InAs QDs grown at 470°C the low integrated PL intensity, the high dispersion of QD sizes in ensemble and, as a result, the large value of FWHM (50-70meV), but the low dispersion of QD ensemble parameters along the line crossed the structures have been detected. In QD structures grown at high temperatures 490-535 °C the high integrated PL intensity, the low dispersion of QD sizes in ensemble and, as a result, less values of FWHM, but the essential dispersion of QD ensemble parameters along the line crossed the structures have been revealed. The reasons of these types of PL nonhomogeneity have been discussed.
Why Structure Matters – Controlling the Properties of Nanoparticle Hybrid Materials
Authors: Choi Jihoon , Dong Hongchen , Matyjaszewski Kris , Bockstaller Michael R 
Published: August 2010

AbstractThe complementary physical properties of the distinct constituents render polymer-grafted nanocrystals (PGNPs) intriguing materials systems in which property characteristics can be tuned over a wide range from hard particulate to soft polymer-type. Here we demonstrate that dependent on the molecular weight and the graft density of the grafted polymer chains, three characteristic regimes of PGNPs are observed: (1) hard-sphere type colloidal crystalline with the formation of cracks driven by short-range interactions, (2) plastic mesocrystalline with the crazing behaviors by chain entanglement, or (3) disordered structure with soft-polymer type interactions. In addition to controlling the mechanical properties of PGNPs, grafted chains can have a key role in mediating their gradual transformation into more ordered microstructures from nanoparticles with energetically unfavorable property (i.e., activation barrier for crystallization induced by polydisperse nanoparticles [1, 2]).
Novel Pre-oxidation Patterning on Thin Aluminium Film Generating Ordered Nanopores through Anodization
Authors: Fois Giovanni , Bolger Ciara Therese , Holmes Justin D , Cross Graham 
Published: August 2010

AbstractAnodic Aluminum Oxide (AAO) is widely employed as a template for fabrication of nanowires and nanotubes due to its ability to generate self organized (SO), well ordered pore structures. We have developed a new aluminum pre-patterning technique to create well ordered nanopore arrays on thin films deposited on silicon substrates. We form patterns of thicker oxide on the surface via local oxidation process using a conducting Atomic Force Microscope (AFM) tip working in contact mode. Pores are forced to nucleate between the pre-oxidized regions during the anodization process. The relation between applied voltage and ordered interpore distance has been found to be linear for these supported thin films. However, the pore spacing is highly reduced compared to free standing foils. A new empiric law has been confirmed for a wide range of voltages, solution concentrations and different electrolytes, including oxalic and phosphoric acid. Our results show that pre-oxidation patterning is an alternative technique to achieve an ordered nanoporous template through the anodization process.
Nano Heterojunctions of Cadmium Sulfide and Cadmium Telluride for Photoelectrocemical Cell Applications
Authors: Demirci Sankir Nurdan , Dogan Bahadir , Parlak Mehmet , Kucukyavuz Zuhal 
Published: August 2010

AbstractThis study presents a very cost effective template-based electrochemical technique to synthesize the nano heterojunctions of cadmium sulfide (CdS) and cadmium telluride (CdTe). SEM analysis revealed that the average length of CdS nanowires varied from 500 nm to 4 μm depending on the deposition time and voltage. Also, average diameter of the CdS nanowires ranged between 100 and 200 nm. The structures of CdS nanowires have been confirmed by XRD and EDX analysis. Photoelectrochemical performances of CdS nanowires revealed that there is a dramatic change in the photoelectrochemical performances with the change in deposition time and voltage. The maximum fill factor (FF) and power efficiency (η) of the CdS nanowires has been calculated as 45 % and 1.36 %, respectively. After the optimization of the CdS nanowire deposition conditions based on the PEC performance, CdTe nanostructures have been deposited on CdS nanowires at various deposition time. SEM analysis showed that CdTe nanostructures have a tendency to grow as nanoclusters. It was observed that the density and the average diameter of the clusters was a strong function of the deposition time. The average diameter of the CdTe nanoclusters after 9-hour deposition reached about 260 nm. The successful heterojunction of CdS nanowires with CdTe nanoclusters have been observed in the SEM analysis. It has been concluded that the PEC performances of the CdS nanowires improved significantly after CdTe deposition. The maximum η, obtained in this study is about 8.04 %. This is one of the highest efficiencies reported in the literature for the nanowire array photoelectrochemical cells.
Magnetization Reversal in NiFe Nano-triangles
Authors: Wang Xinghua , Goolaup Sarjoosing , Cong Chunxiao , Lew wensiang 
Published: August 2010

AbstractWe have fabricated sub-100 nm triangles NiFe triangle arrays using NSL and the MOKE measurement and micromagnetic simulations were carried out to investigate the reversal mechanism of the arrays. Enhancement of coercivity compared to the thin film was observed in all the three arrays but in different degree from the MOKE measurement. With the increase of the lateral size of the triangle, the effect of the coercivity enhancing decreases. Micromagnetic simulation shows that instead of domain wall nucleation and annihilation in the thin film, the reversal mechanism of the 45 and 80 nm triangles is dominated by the coherent rotation. While in the 100 nm triangle, the magnetic reversal takes place via forming and reversing a V like sate.
Evolution, Activity, and Lifetime of Alumina-supported Fe Catalyst During Super Growth of Single-walled Carbon Nanotube Carpets: Influence of the Type of Alumina
Authors: Amama Placidus , Pint Cary , Kim Seung Min , Eyink Kurt , Stach Eric , Hauge Robert , Maruyama Benji 
Published: August 2010

AbstractThe influence of the type of alumina used as catalyst support on the evolution, activity, and lifetime of the catalyst during water-assisted CVD growth (or ‘supergrowth') of single-walled carbon nanotube (SWNT) carpets has been studied. The catalyst consisted of a thin Fe film supported on alumina films deposited by different methods: atomic layer deposition (ALD), e-beam, and magnetron sputtering. In order to fully understand the influence of the type of alumina on SWNT carpet growth, crystalline alumina (c-cut sapphire) and annealed alumina deposited by e-beam were also used as catalyst supports. The activity and lifetime of Fe catalyst during SWNT carpet growth showed a strong dependence on the type of alumina used as support. Fe supported on sputtered alumina (sputtered/Fe) showed the highest catalytic activity and lifetime, which was closely followed by e-beam/Fe while Fe supported on sapphire (sapphire/Fe) showed the least catalytic activity and lifetime. AFM, XPS depth profile, variable angle spectroscopic ellipsometry (VASE) studies revealed that the catalyst evolution and the porosity of the different alumina supports correlate with the lifetime and activity of the catalysts.
Electrically conductive composites via infiltration of single-walled carbon nanotube-based aerogels
Authors: Worsley Marcus A , Kuntz Joshua D. , Kucheyev Sergei , Hamza Alex V , Satcher Joe H , Baumann Theodore F 
Published: August 2010

AbstractMany challenges remain in the effort to realize the exceptional properties of carbon nanotubes (CNT) in composite materials. Here, we report on electrically conductive composites fabricated via infiltration of CNT-based aerogels. The ultra low-density, high conductivity, and extraordinary robustness of the CNT aerogels make them ideal scaffolds around which to create conductive composites. Infiltrating the aerogels with various insulating materials (e.g. epoxy and silica) resulted in composites with electrical conductivities over 1 Scm-1 with as little as 1 vol% nanotube content. The electrical conductivity observed in the composites was remarkably close to that of the CNT scaffold in all cases.