bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Sitox Process and its Application to Advanced MOS Devices
Authors: Lin J. , Chen W. , Banerjee S. , Lee J. , Teng C. , Magee C.
Published: March 2011

In this study, the application of Sllicidation Through OXide (SITOX) process to TiSi2 formation is extensively investigated. The data show that the decomposition of an interfacial SiO2 layer between Ti and the Si substrate depends not only on its thickness but also on the silicidation temperature and the type of dopants in the Si substrate. In general, high annealing temperatures and B-doped p+ Si substrates enhance the decomposition of interfacial SiO2. After the silicidation process, the O concentration at the TiSi2/Si interface is approximately two orders of magnitude higher with SITOX than with the conventional silicidation process. This high interfacial O concentration has no significant effect on the electrical properties of SITOX TiSi2 films and junction diodes. The X-ray Diffraction analysis shows that SITOX TiSi2 films have a polycrystalline structure as do conventional TiSi2 films. The average grain size in a 100 nm SITOX TiSi2 film is estimated to be about 10 μm wide, while that in a 120 nm conventional TiSi2 film is about 3 μm. Histograms of leakage current for junction diodes confirm that the SITOX process can improve the uniformity of leakage currents.
Selective Electroless Metallization of Patterned Ligand Surfaces
Authors: Dressick W. J. , Dulcey C. S. , Calvert J. M. , Georger J. H. , Calabrese G. S. , Thomas M. E. , Stever H. A.
Published: March 2011

A process for creating patterns of metal-binding ligands on a variety of substrates is described. Deep UV patterning of chemisorbed ligand-bearing organosilane films creates modified surfaces that can selectively bind species such as Pd(II) via a covalent metal ion-ligand interaction. Patterned surface-bound Pd(II) is used to initiate additive electroless metallization at the catalytic sites. Metal adhesion to the substrate is controlled by the nature of the catalyst-ligand interaction.
Eiectromigration in Cu/W Structure
Authors: Hu C. -K. , Small M. B. , Ho P. S.
Published: March 2011

Mass transport by electromigration in sputtered Cu line segments on a continuous W line has been measured using the drift velocity technique at temperatures from 166 to 396 °C. The Ta/Cu/Ta line segments are patterned by dry etching techniques. Cu mass depletion (voids) at the cathode end and accumulation (hillocks) at the anode were measured as a function of time from scanning electron microscope micrographs. The edge displacement of Cu was found to increase linearly with time. The activation energy for Cu electromigration drift velocity, which relates to the product of effective charge number and diffusivity, Z*D, is found to be 0.6 eV.
Stress-Related Phenomena in Capped Aluminum-Based Metallizations
Authors: Graas Carole D.
Published: March 2011

The effect of a TiW capping layer on the mechanical behavior of AlSi(l%)Ou(y2%) thin films was evaluated. The aluminum films studied were deposited at temperatures ranging from 150 to 450°C, on various barrier layers (Ti, TiW, and TiN). Measurement of the stacks stress during anneal up to 450°C revealed that for films deposited at 150°C, the capping layer improved yield strength regardless of the type of barrier layer used. The uncapped stacks exhibited the traditional behavior of hillock formation during heating, and hillock /grain collapse during cooling. The capped stacks, however, showed considerably reduced, or suppressed hillock formation during heating, and active tensile stress relief mechanisms during cooling included cracking, voiding, and grain boundary grooving. These observations correlated well with XRD data characterizing the extent of tensile stress buildup in the aluminum films. For films deposited at 300°C, grain deformation during cooling after deposition presumably caused hardening which prevented cracking as well as changes in texture during anneal. This was observed regardless of the presence of a capping layer. Although the stacks studied were unpassivated, this data suggests that capping. layers may enhance stress migration issues in integrated systems.
Silicide Formation with Tungsten Deposited from W-LPCVD; The Role of Back Surface Conditions
Authors: Zhang S. -L. , Östling M. , Smith U. , Buchta R.
Published: March 2011

Tungsten (W) films were deposited on the front surface of float-zone (FZ) Si wafers, from tungsten hexafluoride (WF6) by low pressure chemical vapor deposition (LPCVD). The back surface conditions of the Si wafers was the major concern of this study. Various back surface coatings were investigated, tungsten, thermal SiO2 and LPCVD-Si3N4. Isothermal heat treatments were performed in an argon flow furnace at 760°C for 8 to 30 min. The silicide formation was monitored by Rutherford backscattering spectrometry (RBS). No difference in the silicidation rate was found on the wafers with a back surface oxide layer as compared to that of the reference wafers with no back surface coating. However, for wafers with the back surface covered with Si3N4 or W, a retarded silicidation rate was observed. This phenomenon appeared to be insensitive to the presence of a cap layer (PECVD-SiO2) on the W films before annealing. A model including the behavior of point defects is proposed to provide an explanation to this observation.
Interaction Between Co and SiO2 During Ion-Beam Mixing and Rapid Thermal Annealing
Authors: Dehm C. , Kasko I. , Burte E. P. , Ryssel H.
Published: March 2011

For the application in self-aligned processes, it was supposed that CoSi2 could be superior to TiSi2, since, unlike Ti, a reaction between Co and SiO2 was not observed up to now. We studied the reaction of Co and SiO2 during ion-beam mixing and rapid thermal annealing (RTA). The influences of As and Ge implantation energy and dose were investigated in the range of 50 to 200 keV and 1–1014 to 5–1015 cm2. The annealing temperature was varied between 700° C and 1100°C.

It could be demonstrated that the Co concentration in SiO2 rises with increasing Ge and As energy and dose up to values of 5·1015 cm2 compared to 2·1012 cm2 in unim-planted, annealed samples. The Co profiles in SiO2 were also studied by secondary ion mass spectroscopy (SIMS) and compared with Monte-Carlo simulations indicating pure ballistic mixing. Plan-view and cross-section transmission electron microscopy (TEM) were used to examine the SiO2 surface as well as the Co-SiO2 interface. These investigations revealed that ion-beam mixing with doses at or above 5·1014 cm2 and subsequent annealing does not damage the SiO2 unlike to unimplanted, annealed samples which show a rather severe structural change of the SiO2 surface increasing with rising annealing temperatures.
Metalization of Oriented Crystalline Films on Amorphous SiO2/Si
Authors: Luo Li , Nastasi M. , Maggiore C. J. , Pinizzotto R. F. , Yang H. , Namavar F.
Published: March 2011

To meet the needs for vertical integration in microelectronic devices, metalization should not only provide required conducting properties, but should also be suitable for further epitaxial growth so that multilayer structures or heterostructures can be formed. For Si based electronic devices, this has been hindered by the amorphous nature of SiO2. SiO2 layers have been extensively used to passivate the Si surfaces and act as dielectric insulators for forming integrated circuits. In this study, we show that high quality, oriented, metallic nickel disilicide (NiSi2) thin films can be formed on SiO2/Si by combining both ion implantation and e-beam evaporation techniques. The orientation of the Si substrate is maintained in the NiSi2 film as if the SiO2 is not present. RBS/ion channeling and TEM were used to characterize the structures formed and the results indicated that the metallic NiSi2 films were comparable with the films made directly on Si under the same deposition condition. This method should, in general, be applicable to other suicides that have been epitaxially grown on Si.
Deposition of tungsten on silicon dioxide by GeH4 reduction of WF6
Authors: Oosterlaken T. G. M. , Leusink G. J. , van der Jeugd C. A. , Janssen G. C. A. M. , Radelaar S.
Published: March 2011

Chemical Vapour Deposition of tungsten on silicon dioxide by means of GeH4 reduction of WF6 is studied. The influence of the ambient gas on the nucleation of tungsten is examined. Experiments have been performed in both Ar and H2 ambient. It is found that an Ar ambient hinders nucleation on silicon dioxide in comparison with a hydrogen ambient. Adhesion of the film and uniformity over the wafer are acceptable for the films deposited in hydrogen ambient.
Hetero n-i-p-i Structures for Nonlinear Optics and for Studies of Charge Carrier Transport
Authors: Kost Alan
Published: March 2011

The use of large optical nonlinearities in hetero n-i-p-i structures to study charge carrier transport is discussed. A short history of hetero n-i-p-i's and a summary of related semiconductor microstructures are also presented.
Application of Surface Photovoltage Spectroscopy in Surface Analysis
Authors: Baikie Iain D. , Venderbosch Eimert , Hall Birgitta
Published: March 2011

Extension of the Kelvin probe vibrating capacitor technique of measuring work function, via Illumination of the semiconductor surface, i.e., Surface Photovoltage Spectroscopy (SPS), has many potential applications in the field of surface analysis.

The combination of broad-band (white) and monochromatic radiation, together with measurement of the dark signal permits complete characterisation of the semiconductor work function via determination of the electron-affinity, surface potential and Local DensIty-of-States (LDOS). The work function is an extremely sensitive indicator of a wide range of surface processes, e.g., particle adsorption, stress, defect creation, phase-transitions, etc.

We Illustrate application of this technique in the study of the temperature dependent initial oxidation behaviour of p-type Si(111) 7×7 between 100 and 300 K. The SPV response of the clean surface at 100 K corresponds to the capture of photo-stimulated electrons by a band of surface states centered around 1.4, 1.7, 1.9 and 2.4 eV. This response completely disappears at the peak of the (dark) work function change (0.3L) corresponding to a near complete removal of dangling bond states. The temperature-dependent white-light SPS response permits determination of the band-bending throughout the adsorption process. We observe that at 100 K the band-bending substantially decreases during the initial adsorption phase (0.1 L), after this dose it remains constant. However at 300 K the band-bending decreases much later, i.e., >10 L, in conjunction with oxygen permeation through the surface layer.

In conclusion Surface Photovoltage Spectroscopy SPS is a simple and flexible method which can be used to follow the rather complex changes occurring at the semiconductor surface. It is a non-contact, nondestructive technique which allows simultaneous determination of both semiconductor band-bending and electron affinity.
A Computer Assisted Study of Chaotic Behavior in Intrinsic Photoconductors
Authors: Serfaty Alicia , Joshi N. V. , Martin J. M.
Published: March 2011

The present work confirms thee possibility of chaotic behavior in intrinsic photoconductors with one type of traps under high radiation intensity. The system shows two attractors and a strong sensitivity to the initial conditions.
Applying Kukhtarev's Charge Transport Model to Multiple Quantum-Well Hetero-Nipis
Authors: Mahgerefteh Daniel , Garmire Elsa
Published: March 2011

We present a model for light-induced charge transport in long-period multiple-quantum-well hetero-nipi structures that is based on Kukhtarev's transport model developed for understanding photorefractive grating formation. We give a simple analytical expression for the steady-state space-charge field in a hetero-nipi under illumination as a function of light intensity.
Study of the Inhomogeneities in Semiinsulating GaAs and InP by Spatially Resolved Photoconductivity
Authors: Gonzalez M. A. , Jiménez J. , Martin P. , Sanz L. F. , Chafai M. , Avella M.
Published: March 2011

A high resolution spatially resolved photocurrent system to study bulk non homogeneities in semiinsulating GaAs and InP is described. [Fe+3] distribution is studied in InP. In undoped LEC semiinsulating GaAs a study of the relation of Photoquenching (PQ) and Enhanced Photocurrent (EPC) to the dislocation atmosphere is done.
Prospective Conducting Polymer Composite Materials
Authors: Ponomarenko Anatoliy T , Shevchenko Vitaliy G. , Kryazhev Yuri G.
Published: March 2011

Influence of processing conditions on electrophysical properties of composite materials (CM) have been investigated. Metal powders, graphite, Z-ferrite and other fillers were used. Properties of CM were investigated in direct and alternating electromagnetic fields.
Electro-Optics, Photoconductivity and the Photorefractive Effect
Authors: Goossen K. W. , Haegel N. M. , Nolte D. D.
Published: March 2011

This symposium was established as an interdisciplinary forum to foster lines of communications among three separate research communities. These communities are: 1) the electro-optic community, 2) the photorefractive community, and 3) the photodetector community. In each of these fields microscopic electric fields are generated inside semiconductor materials by illumination.
Vacuum Electroreflectance: Overcoming the Difficulties of Electrolyte Electroreflectance and Photoreflectance
Authors: Mioc Silvia L. , Raccah Paul M. , Garland James W.
Published: March 2011

A new technique for obtaining the electroreflectance (ER) spectrum, Vacuum Electroreflectance (VER), is introduced. In VER, the modulating electric field is applied capacitively using a transparent electrode as one plate and the sample as the other plate, with vacuum in between. In this geometry, cooling or heating is achieved without any sample preparation. Precise positioning is achieved by piezoelectric motors monitored by a HeNe interferometer, and cooling to 80 K by the Joule-Thompson effect. GaAs samples with different Si doping are used to compare VER to Electrolyte ER and Photoreflectance.
Controlled Growth of GaAs/AlAs(111)B Superlattices
Authors: Angelo J.E. , Hoehn J.W. , Dabiran A.M. , Cohen P.I. , Gerberich W.W.
Published: March 2011

In this study, transmission electron microscopy (TEM) was used to investigate the growthconditions which produce the highest quality GaAs(111)B films by molecular beam epitaxy (MBE). Low-temperature growth using both As4 and arsine as an As2 source produced highly twinned structures, although the use of As4 provided for a smoother surface and slightly different defect structure. Two distinct twin boundaries, (112)A and (112)B, were identified by cross-sectional transmission electron microscopy (XTEM). The (112)A defect could be over-grown by a subsequent high temperature growth but the roughness associated with the (112)B defects only increased with further growth. High temperature growth of GaAs and AlAs films, while maintaining the GaAs(11)surface reconstruction, resulted in substantial reduction in the number of twins boundaries. We also found that GaAs(111)B layer quality and surface morphology can be further improved by a high temperature growth with low arsenic to Ga flux ratio of I to 1.5 ona slightly misoriented substrate.
Method of GaAs Growth on Single Crystal Si Substrate
Authors: Dorogan Valery V. , Kosyak V.A. , Trofim V.G.
Published: March 2011

In the proposed method space and time temperature gradients are used for GaAs epitaxial deposition on Si substrates from liquid phase. Minimal Si substrate dissolution and preferential GaAs deposition from the liquid phase on Si substrate can be obtained by selecting dissolvents, requiring necessary gradients temperature values and times of active phases interaction. Because of nonuniformities in the etched Si substrate surface act as crystallization centres, the deposition process begins from GaAs island growth. Due to the dominate tangential growth rate, the separate single crystals coalesce into a GaAs monolayer.
MOVPE Growth of GaAs on Si Using Tertiarybutylarsine
Authors: Miyagaki S. , Ohkubo S. , Takai K. , Takagi N. , Kimura M. , Kikuchi Y. , Eshita T. , Takasaki K.
Published: March 2011

We developed GaAs heteroepitaxy on a Si substrate by metalorganio vapor phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs). When we preheated Si at 1000ºC in the atmosphere including TBAs, a carbide layer was formed on the Si surface. This led to polycrystalline GaAs growth. By carrying out high-temperature preheating in an H2 -only atmosphere and supplying TBAs after the preheating, we have successfully grown single-crystal GaAs with a mirror surface in a process completely free of AsH3.
A New Method of Identifying the Interfacial Structure in the Type-B CoSi2//Si(111) Bicrystal
Authors: Daykin A.C. , Kiely C.J.
Published: March 2011

A new method of identifying the interfacial structure in the type-B CoSi2//Si(l11) bicrystal is presented. It involves using the kinematic structure factor equation to calculate the levels of contrast which will arise in darkfield micrographs due to steps at the interface. These are then matched to the levels of contrast measured directly from experimental images using an optical densitometer. By analysing the contrast levels measured from the same region of the bicrystal in both g=400B-aCos2 and g=111B-aCos2 micrographs, it is shown that the experimental resultsare consistent with the 7-fold coordinated interfacial structure.
Formation of (1120) ZnO Films by Controlling the Selftexture and the Relaxation of Film Stress
Authors: Yamaguchi Takao , Fujimura Norifumi , Goto Seiki , Ito Taichiro
Published: March 2011

ZnO film has a tendency to grow parallel to the <0001> axis. Therefore, it is difficult to obtain epitaxial or oriented films with any other orientation. Nevertheless, we obtained excellent epitaxial (1120) ZnO films on R-cut, (0112), sapphire by controlling the self-texture. Epitaxial (1120) ZnO on R-cut sapphire exhibits an anisotropic misfit at the interface. To clarify the growth mechanism, the stress relaxation was calculated by measuring the curvature of the substrate and the lattice spacings. The change in stress calculated by these two methods differs from each other. We discuss this discrepancy in terms of the growth mechanism.
Morphology and Low Temperature Electrical Transport in Heteroepitaxial Indium Nitride Films
Authors: Bryden W. A. , Ecelberger S. A. , Kistenmacher T. J.
Published: March 2011

The correlation of low temperature electrical transport with the evolution of heteroepitaxy and morphology for sputtered indium nitride thin films has been studied. A series of indium nitride films were deposited at temperatures ranging from 50 -650 °C by reactive rf magnetron sputtering onto the (00.1) face of sapphire. Above 350 °C, a transition occurs from a continuous morphology, in which grains are in intimate electrical contact, to an open, porous morphology with poor electrical contact. This transition in morphology deeply affects the electrical transport of the semiconductor. At low deposition temperature, the electrical transport is dominated by the relatively weak intergrain scattering leading to films with moderate mobility. As the deposition temperature is raised, the increasingly porous nature of the film leads to a deterioration in electrical mobility. It is proposed here that the relevant physics of these films is analogous to that for granular solids with a distribution of electrical connectivities that suggests a scattering potential dominated by disorder. In fact, the temperature dependence of the resistivity is found to be analogous to that observed in disordered and amorphous materials. In particular, the resistivity is characterized by: 1) A very weak temperature dependence; 2) The observation of a resistance minimum; and, 3) A steep rise in the low temperature (<4K) resistivity that follows a T1/ dependence.
Partial Dislocations and Critical Thicknesses for Strained Layer Relaxation
Authors: Hwang D. M. , Bhat R. , Schwarz S. A. , Chen C. Y.
Published: March 2011

Partial dislocations and their associated stacking faults are identified as the primary defects responsible for the initial relaxation of tensile-strained layers of fcc structure. The critical thickness for the formation of 90° partial dislocations at the strained interface is almost a factor of two smaller than that predicted for the formation of 60° perfect dislocation. Microstructures revealed by transmission electron microscopy from strained layers of various lattice mismatches and thicknesses agree with the prediction of the standard free-energy minimization model.
Detection of Misfit Strain Relaxation in MBE Grown Si1-xGex Films by Dynamic Monitoring of Rheed Diffraction Features
Authors: Maes J.W. , Schannen O.F.Z. , Trommel J. , Werner K. , Radelaar S. , Balk P.
Published: March 2011

Reflection high energy electron diffraction (RHEED) has been used to detect strain relaxation in SiGe during growth on <001>- oriented Si for various layer compositions and substrate temperatures. The RHEED-technique permits the dynamic monitoring of the in-plane lattice constant of the growing layer by measuring the distance between diffraction features. The actual RHEED pattern is recorded by a CCD camera and subsequently processed in real time by a computer. This way, the layer relaxation can be followed conveniently; a detection limit for a variation in the lattice constant of Δa/a=5.10−4 has been obtained.
Control of threading dislocations in lattice-mismatched heteroepitaxy
Authors: Schowalter L.J. , Taylor A.P. , Petruzzello J. , Gaines J. , Olego D.
Published: March 2011

It is generally observed that strain relaxation, which occurs by misfit dislocation formation, in lattice-mismatched heteroepitaxial layers is accompanied by the formation of threading dislocations. However, our group and others have observed that strain-relaxed epitaxial layers of In1−xGaxAs on GaAs substrates can be grown without the formation of threading dislocations in the epitaxial layer. We have been able to grow strain-relaxed layers up to 13% In concentration without observable densities of threading dislocations in the epilayer but do observe a large number of dislocations pushed into the GaAs substrate. The ability to grow strain-relaxed, lattice-mismatched heteroepitaxial layers has important practical applications. We have succeeded in growing dislocation-free layers of ZnSe on appropriately lattice-matched layers of In1−xGaxAs.
Molecular Beam Epitaxy Growth and Structural Characterization of Si/GaAs Superlattices
Authors: Matyi R.J. , Gillespie H.J. , Crook G.E. , Wade J.K.
Published: March 2011

The growth of high quality Si/GaAs superlattices on GaAs substrates using molecular beam epitaxy is described. A typical superlattice structure consisted of ten periods of thin (<5Å) layers of pseudomorphic silicon alternating with thick GaAs layers; typical GaAs thicknesses range from 100Å to 1850Å. In situ reflection high energy electron diffraction analysis of the structures during growth showed the silicon layers developed a (3 ×1) reconstruction, while the GaAs exhibited a (4×2)→(3×2)→(3×1)→(2×4) reconstruction sequence. Both observations agree with prior studies of the growth of embedded silicon in GaAs/Si/GaAs heterostructures. X-ray diffraction using the (004) reflection showed sharp and intense satellite peaks (out to 22 orders in one case), indicating a high level of structural quality. Very good agreement has been obtained between observed diffraction patterns and those calculated via dynamical simulation.
The Effect of Photoreactive Substituents on the Morphological Structure and Properties of BPDA-PPD Based Polyimides
Authors: Coburn John C. , Pottiger M. T. , Nader A. E. , Pryde C. A.
Published: March 2011

Adding photoreactive substituents onto a biphenyldianhydride (BPDA) and p-phenylene diamine (PPD) poly(amic acid) precursor influences the onset of imidization and the development of anisotropy and crystalline morphology during processing and the resulting morphology and properties of the fully cured films. Amine salts shift the imidization to lower temperatures while the covalently bonded esters shift the imidization to slightly higher temperatures. Anisotropy of the photosensitive polyimides develops at higher cure temperatures compared to the poly(amic acid). The photoreactive substituents do not affect the crystal structure, but do influence the crystallite orientation and morphology. Out-of-plane coefficients of thermal expansion (CTEs), calculated from the volume expansivities of these systems, are an order of magnitude larger than the in-plane CTEs.
Water Transport Across Modified Polyimide Surfaces: Ion-Bombarded PMDA-ODA and BPDA-PDA
Authors: Clearfield H.M. , Furman B.K. , Bailey F. , Sheth N. , Purushothaman S.
Published: March 2011

Durability of metal/polyimide (PI) interfaces is essential for the long term reliability of advanced microelectronics packages. In earlier work, we showed that water absorbed by the PI can affect durability because, at high temperatures, it migrates to the interface and oxidizes the metal. In this study, we have investigated water transport through PMDA-ODA and BPDA-PDA polyimides as a function of ion beam treatment. Thermal desorption mass spectrometry (TDS) and gravimetric water uptake measurements were correlated with XPS spectra obtained from modified films. Transport through films with unmodified surfaces is rapid as shown by water uptake, however uptake is slowed considerably by surface modification. Additionally, only modified films exhibit peaks in TDS spectra–the peak temperature and intensity scale with dose. High resolution XPS spectra taken after modification suggest a graphitic-like surface region independent of dose. However, the extent of this “damaged” region scales with the dose. From the TDS spectra, we determine that the activation energy for water diffusion through this layer is 12–15 kcal/mol.
Fatigue Failure Mechanisms in Pb95.5Sn2Ag2.5Solder Joints: a Combined SIMS/XRD Study
Authors: Scandurra A. , Torrisi A. , Spoto G. , Fragala I. , Puglisi O.
Published: March 2011

The effects of accelerated fatigue tests on the crack formation in 95.5%Pb-2%Sn-2.5%Ag and 95%Pb-5%Sn solder joints have been investigated. The fracture surfaces which form upon mechanical stress have been studied by SIMS and XRD techniques. They are always located in the solder layer and show grain growth of the Pb-rich α phase present in the phase diagram of the Pb-Sn and the Pb-Sn-Ag systems. Grain growth is accompanied by tin depletion. XRD patterns of samples after 1, 40, 80 fatigue cycles show no variations of lattice parameters of the phases present in the alloy thus ruling-out the formation of new phases under mechanical stress.
A New, Reliable Snap Cure Die Attach Adhesive.
Authors: Galloway David P. , Nguyen My N.
Published: March 2011

With the advent of new in-line assembly techniques and equipment such as high temperature wirebonders, equipped with rapid cure stations, came the need to develop a suitable, adhesive with high performance characteristics. Typical traditional die attach adhesives were found to be inadequate.

The higher performance characteristics were determined by assembly characterization studies. A new type of rapid cure thermoset dieattach adhesive was then developed to fill the need of these more rigorous assembly requirements.

Early testing showed the new material to possess the desired attributes, such as < 1% wt loss during cure, thermal stability well above 300°C, low ionic species and excellent adhesion strength after cure. In addition, the material is suitable for syringe dispensing at high speeds.

In this paper, we will review the process performance goals, the material evaluation strategy, the various types of screening tests performed on all samples, and some of the findings from the assembly characterization studys. We will conclude with the reliability test results, comparing this new material with four other die attach adhesive samples. Emphasis is given to the overall success of using this evaluation strategy and to the reliable results of this new adhesive used in plastic Dual-in-line packages.
Electro-Optic Polymer Devices
Authors: Lytel Rick , Lipscomb Ferris , Ticknor Tony
Published: March 2011

Electro-optic (EO)polymers, processed into thin multilayer films, exhibit large nonresonant EO coefficients and low dielectric constants from DC to multi-GHz frequencies. Orientation of the constituent nonlinear optical chromophores, usually accomplished by electricfield poling, provides an EO coefficient suitable for modulation of light beams propagating in the plane of the polymer film. Thus, EO polymers are ideally suited for applications in integrated optics.

The field EO polymer integrated optics has been developing rapidly during the past several years. Recent advances include the formulation of poled crosslinked epoxies and guest-host polyimides exhibiting thermal stability at temperatures significantly higher than those previously achieved with thermoplastic acrylate chemistry. These developments are an essential first step toward achieving practical materials exhibiting stability to manufacture, assembly, and end-use in modem electronic systems applications. This paper provides an introduction to EO polymer waveguide devices for applications to electronic packaging and interconnection.
Photosensitive Dielectric Film Developed Using a Polymer Blend
Authors: Tani M. , Miyahara S. , Horikoshi E. , Natori K. , Sato T.
Published: March 2011

We developed a photosensitive film using a polymer blend for use in applications that require a high density of interconnects. Our film can be used as a dielectric or a passivation layer in high density packaging technologies. We formed vias about 20 μm in diameter using our new materials.
Deposition, Characterization, and Application of Aluminum Nitride Thin Films for Microelectronics
Authors: Yu C. , Kim S. , Meikle S. , Doan T. T. , Blalock G.
Published: March 2011

In this paper we report on a high rate (˜ 100 nm/min) aluminum nitride (AIN) deposition process, as well as several novel applications of AIN thin films for microelectronics and optoelectronics applications. Surface morphology and chemical composition, etchability, etch selectivity to oxide, and step coverage at various deposition temperatures have been investigated by atomic force microscope (AFM), scanning electron microscope (SEM) and Auger spectroscope (AES). In addition, for the first time, chemical mechanical polishing (CMP) of AIN films has been carried out and a polishing rate of 270 nm/min has been achieved. Results of several novel processes involving AIN as an etchstop layer in microelectronics and as an optical interconnection in opto-electronics will be presented.
Low TCE Polyimides from Polyamic Acid Blends and Copolymers: Preparation and Characterization Studies
Authors: Sachdev Krishna G. , Graham-Ode Sandra , Nunes Thomas L. , Ho Paul S.
Published: March 2011

A series of polyimides prepared from BPDA-PDA and BTDA-PDA polyamic acid blends and the corresponding (BPDA-PDA)x-(BTDA-PDA)y copolymers have been investigated for the mechanical properties, the thermal expansion, and the residual stress in films cured on silicon wafers. To determine the effect of inclusion of a highly flexible chain segment into BPDA-PDA structure, a BPDA-PDA/BDAF copolyimide has also been characterized. The experimental data are correlated with the chemistry and the composition of the blends and the copolyimides.
Liquid Etch of Moisture Resistant Polyimides
Authors: Fjare D. E. , Beuhler A. J. , Navar C. A.
Published: March 2011

A new wet patterning technology which is particularly well suited to moisture resistant polyimides is described. The key feature is a two step wet-etch with the photoresist patterned and the amic acid etched in sequential steps. A higher degree of sidewall control than previously attained is possible because the etchant can be tailored specifically for the polyamic acid. The etchants operate by the polarity shift mechanism conventionally used to etch polyamic acids with hydroxide bases, but instead use the weaker aliphatic amines as the active base component. Alcohols are used to adjust the polarity of the solvent.
Effects of Several Ingredient Variables on Mechanical Properties of Wood Fiber-Polyolefin Composites Blended in a Thermokinetic Mixer
Authors: Gonzalez C. , Clemons C. M. , Myers G. E. , Harten T. M.
Published: March 2011

We examined the influence of several variables on the mechanical properties of wood fiber-polyolefin composites blended in a thermokinetic mixer. A pure cellulose fiber and fibers from old newspaper provided similar performance in matrices of virgin polypropylene or recycled milk bottles (high density polyethylene). Relative to wood flour, these fibrous fillers led to greater strength and modulus with both plastics, to lower impact energy with polyethylene, and to similar impact energy with polypropylene. Compared with the existing commercial wood flour-polypropylene system, the totally recycled polyethylene-newspaper composite provided equivalent strength and modulus, along with greater notched impact energy. Little difference was seen in composites containing a maleated polypropylene additive in the form of the solid anhydride or the emulsified potassium salt, indicating that the additive acted as a dispersing agent and not as a strong coupling agent.
Adhesive Contaminants (Stickies) and Methods for Removal
Authors: Klungness John H. , Doshi Mahendra R.
Published: March 2011

A variety of adhesive contaminants (“stickies”) are encountered in wastepapers. They are broadly classified as hot melts, pressure-sensitive adhesives, and lattices. Their properties and control methods are discussed. Specifically, control methods include furnish selection, improved pulping and deflaking, well-designed screening and cleaning systems, and dispersion and additives to detackify or stabilize stickies, or both. A new technology is also discussed regarding it's possible application for controlling stickie contaminants. Test methods for measuring stickies are also reviewed.
Investigations by Glass Sensors on the Corrosive Environmental Conditions at Stained Glass Windows with Protective Glazings in Europe
Authors: Leissner Johanna , Fuchs Dieter R.
Published: March 2011

At 15 prominent churches and cathedrals in 7 European countries the environmental corrosive stresses at the stained glass windows were assessed by glass sensors. Special emphasis was given to the protective properties of different types of protective glazings. The obtained total stress level data, based on MI-glass sensor measurements, help to conclude on the appropriate choice of the ventilation systems and give information about specific environmental impacts. The results indicate that internally ventilated protective glazings have a higher protective effect than externally ventilated systems. The nonventilated type of protective glazing even raised the corrosive stresses for the stained glass windows.
Science of Art and Analysis: A Mixture for Undergraduate Non-Specialists
Authors: Taft W. Stanley , Mayer James W.
Published: March 2011

At Cornell University we are in the third year of teaching an interdisciplinary, undergraduate course on the physical properties and structures of works of Art, and the modern analytical methods used to investigate them: Art, Isotopes, and Analysis. The challenge is to explain concepts familiar to museum scientists and conservators to a group of 150 undergraduate students with a background that ranges from Art History to Computer Science. Painting techniques (Fresco, Tempera, Oil, etc.) are demonstrated to the class. The analytical techniques involve the interactions of electrons, photons, ions and neutrons with pigments and other materials. This instructional approach serves as an introduction to published analyses of works of art.
The Gulf War and its Aftermath on the Cultural Heritage of Iraq
Authors: Al-Radi Selma M. S.
Published: March 2011

The damage caused during and in the aftermath of the Gulf War to the cultural monuments and heritage of Iraq resulted directly from the bombing. Some of the effects were immediate, the rest were due to delayed reactions to the vibrations. However, the most serious loss to the country took place during the insurgencies immediately after the war was over when nine provincial museums were looted and robbed of their objects. In all some 4000 objects are missing. Although many will have been destroyed during the upheavals, others have begun to appear on the antiquities markets in the West.
Catastrophes and Entropy of Cultural Properties
Authors: Benarie Michel , Druzik James R.
Published: March 2011

“The wear of iron teeth of time...”

“nothing is eternal”

“everything ends up in ashes”

Such poetic locutions have been with us since Biblical and Homeric times. Lately it has become fashionable to clad this commonplace insight in more scientific garb such as the Second Law of Thermodynamics
Non-Destructive X-Ray Diffraction with 30-Micron Spatial Resolution: Some Examples
Authors: Inaba M. , Miyata J. , Sugisita R.
Published: March 2011

We have been measuring x-ray diffraction spectra of small samples of layers in cross-sections using a Micro X-ray diffractometer (PSPC/MDG) system since 1988. In measuring with xray diffractometry, the position sensitive proportional counter (PSPC) covers 150 degrees of x-ray diffraction, continuously. The data are accumulated by the multichannel analyser (MCA) and monitored on a CRT during the measurement period. Mounted samples can rotate around three axes. The XRD spectra are very like those from a wide angle goniometer used in powder diffraction. Normally the spatial limits are around 30 microns in diameter, as we have found experimentallly in our samples. We feel this system is very feasible for art and archaeological studies. Some case studies are presented.
Detection of Delaminations in Art Objects Using Air-Coupled Ultrasound°
Authors: Murray Alison , Fortunko C.M. , Mecklenburg Marion F. , Green Robert E.
Published: March 2011

The possibility of using air-coupled ultrasound to find delaminations between layers in paintings was investigated. Simulations of modern paintings were constructed with hardboard as the support layer, and a layer of gesso, an animal hide glue and chalk, as the upper layer. Delaminations were introduced between the two layers. Scanning the samples using air-coupled ultrasound clearly showed these flaws. A transmitting transducer, which was 25 mm in diameter and had a focal length of 51 mm, was placed 11 mm from the back surface of the sample and an identical receiving transducer was placed 51 mm from the front surface. The transducers were operated in a tone burst mode at a center frequency of 475 kHz. Signal enhancement techniques were used to improve the contrast of the data.
Modern Transparent Papers: Materials, Degradation, and the Effects of Some Conservation Treatments
Authors: Reyden Dianne Van Der , Hofmann Christa , Baker Mary , Mecklenburg Marion
Published: March 2011

Modern transparent papers, also known as tracing papers, require specific chemical and physical properties, such as translucency, smoothness, and whiteness, which are produced by specially formulated compositions and manufacturing procedures. Ironically, these special formulations may in some ways render such papers susceptible to problems from damage and degradation, while also making them particularly reactive to moisture and solvents that must be used in conservation treatments to correct these problems. In order to evaluate the effects of water and organic solvents on such papers, four research projects were designed to consider the variables of paper composition, properties, type of solvent, technique of application of solvent, and flattening. This paper summarizes findings on materials characterization, degradative effects of aging, and some effects of solvents used on transparent papers for stain reduction, humidification, and flattening.
The Hague Convention of 1954: History, Significance and Compliances
Authors: Corzo Miguel Angel
Published: March 2011

The UNESCO Convention for the Protection of Cultural Property in the Event of Armed Conflict, signed at the Hague in 1954, is a document that reflects 20th century thinking on the means to safeguard the world's cultural heritage. It is our task to transform it into one that anticipates the challenges of the 21st century. First, then, we should pay homage to those individuals who had the spirit and the resolve to formulate the Convention and its Protocol. Second, we should admit that the Convention's effectiveness has been minimized in the past, largely due to a Euclidean conceptualization of the problem when in fact during war the axioms become spontaneously non-Euclidean, non-linear and highly chaotic. Clearly there is a need to reevaluate its premises in fresh ways, and to strengthen it in the context of the New Age that shall define the future.
Third Millennium B.C. Tin Processing Debris From Goltepe (Anatolia)
Authors: Vandiver Pamela , Yener K. Aslihan , May Leopold
Published: March 2011

Ceramic remains of fragmentary vessels, believed to be smelting crucibles based on microscopic field investigation, were analyzed using a variety of techniques in order identify the metal being processed and to reconstruct the ancient processing, especially ranges of composition, temperature, atmosphere, and the constraints on processing which each of these processing variables would have imposed. The identification of the metal being processed in the crucible surface residues and the slags provide data to resolve a dispute over the nature of the ancient metallurgical processing at Goltepe; gold and iron have been suggested as alternate metals but were not found. Intensive study of the ceramic and slag microstructure, composition and thermal history was required to establish the processing constraints which will be used to aid future replicative smelting experiments at the site.
Thermal Analysis of Early Neolithic Pottery From Tepe Ganj Dareh, Iran
Authors: Yelon A. , Saucier A. , Larocque J.-P. , Smith P.E.L. , Vandiver P.
Published: March 2011

A series of pottery fragments from an early Neolithic site in Iran is analyzed to determire the original baking temperatures. Two magnetic techniques are used: remanent magnetization decay, and hysteresis loop analysis. The results are complementary, although some are, at first sight, contradictory. The causes of these apparent contradictions are explained. The analyses confirm that the pottery was baked under highly variable conditions, probably over open fires. Control of baking was poor, and there was considerable variability not only from one vessel to another but even from one zone to another on the same vessel. Our results suggest the need for caution in interpreting often ambiguous findings in this field of ancient technology.
The Technical Examination of Some Neolithic Chinese Liangzhu Ceramics in the Harvard University Art Museums Collection
Authors: Dajnowski Andrzej , Farrell Eugene , Vandiver Pamela
Published: March 2011

At the Neolithic archaeological site at Liangzhu in China, located 16 kilometers northwest of Hangchou in Cheking province, many objects of stone, jade, and black pottery were discovered between 1936 and 1939. While the exact date of the Liangzhu culture is uncertain, it is considered to be between 3500 and 2000 BC. A characteristic feature of the Liangzhu-culture pottery is a thin black finish and a layered structure of the body consisting of a black core sharply changing to a gray or red band ending in the black surface.

The focus of this paper is to explain why the cores of the vessels are black and why the colored bands occur and what they indicate about the firing conditions of the pottery. Analyses were ca rried out using SEM, electron-beam microprobe, X-ray diffraction, photo-electron spectroscopy, and polarizing microscopy. From this evidence, it is clear thait a clay vessel containing abundant charcoal was thrown on the wheel and then fired under reducing conditions so that charcoal was retained and iron reduced. Just before completion of the firing or during the cooling phase, air was allowed to enter the kiln and a limited thickness of the outer core was oxidized. Then, for decorative purposes, the surface was heavily smoked, and/or a thin iron-containing slip layer was reduced in smoke and burnished.
A Technological Marker of the Penetration into North America: Pressure Microblade Debitage, its Origin in the Paleolithic of North Asia and its Diffusion
Authors: Inizan M-L. , Lechevallier M. , Plumet P.
Published: March 2011

Until recently1it was admitted that the pressure debitage technique had been invented at the end of the Upper Paleolithic, and its presence in different geographical zones was difficult to explain.

Now that we are able to recognize it thanks to advances in experimentation, its invention seems to have been made some 20,000 years ago in the vast area where the Mongoloid people, who were to occupy the Far East, the Beringian zone and America, first appeared.

We are going to describe the methodological approach which allowed us to imply pressure debitage as a cultural marker in the history of prehistoric penetration into North America and to show the specificity of this technique in the Paleolithic of North Asia. Our proposal is a development of an unpublished paper presented at the Novosibirsk Symposium in 19902. The opportunity we had then to examine lithic industries from Siberia convinced us of the early use of the pressure technique.
The Diversity of Newly Discovered Deterioration Patterns in Ancient Egyptian Pigments: Consequences to Entirely New Restoration Strategies and to the Egyptological Colour Symbolism
Authors: Schiegl Solveig , Weiner Karl L. , Goresy Ahmed El
Published: March 2011

Polished cross sections through more than 1000 pigment samples from ancient Egyptian monuments (5th Dynasty to Roman Times) were investigated in reflected light, with SEM, and with electron microprobe techniques (EMPA). These combined analytical techniques allow many insights into the painting layers and down to the substrate. Textural relations of both the primary paintings and of the deterioration products can then be delineated. They also discern the stages of the various deterioration processes and the degree of damage of the painting layers.

The textural patterns of six deterioration processes not known before are discussed in detail and are documented in BSE-micrographs. Five of these processes commence in synthetic Cu-pigments (Egyptian Blue, glass pigment, and Green Frit) and Fe-bearing glass pigments. The 6th process leads to the formation of complex phosphates and is mainly exogenous. It causes severe damage to natural and synthetic pigment layers. These processes result in destruction of the primary pigments and coloured decorations.

Consequences as to the colour symbolism and future treatment of befallen paintings are discussed.
Some Applications of Ion Chromatography to the Study of the Deterioration of Museum Artifacts
Authors: Tennent Norman H , Cooksey Brian G , Littlejohn David , Ottaway Barbara J
Published: March 2011

Ion chromatography has been applied to the investigation of corrosion and efflorescence products on a range of museum artifacts whose deterioration is due to reaction with organic carbonyl pollutants in the storage environment. The potential of the technique and its optimisation for the determination of chloride, acetate, formate, nitrate and sulphate anions and associated cations are reported. Compounds containing acetates and/or formates from ceramic, geological, mollusca and metal collections have been investigated. The utility of ion chromatography for the examination of specimens which show no visible efflorescence, but from which significant acetate and formate levels can be quantified, is also demonstrated. The complementarity of ion chromatography and other techniques, in particular X-ray diffraction and infra red spectroscopy, for the investigation of efflorescence products is emphasised.