bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of Cofired ALN Multilayer Substrates at Low Temperature Sintering
Authors: Terao Koichi , Uchiyama Ichiro , Hamano Akihiro 
Published: March 2011

AbstractIn order to lower the firing temperature of W cofired AlN multilayer substrates, sinterabilities of AlN substrate material and W conductor were investigated at low sintering temperatures around 1650 •C.In case of AIN substrate material, the effect of AIN powder properties on sinterability and thermal conductivity was evaluated. The powders, with specific surface area between 2.3 and 8.2m2• g−1 and oxygen content between 0.7 and 3.2 wt%, were sintered with CaO and Y2O3 as sintering additives. The finer powder promoted the densification below 1600°C and each powder was fully densified at 1650°C. However thermal conductivity sintered at 1650°C decreased with decreasing particle size due to increasing oxygen content inside AlN grains. The thermal conductivity of optimized AlN substrate sintered at 1650°C had over 100W • m−1 K−1.W conductor is required dense microstructure for high adhesion strength to AlN substrate. Shrinkage mismatch between AlN and W during sintering caused porous microstructure for coarse W powders or detaching for fine W powders. The optimized W paste was developed for low temperature sintering.
Aluminum-Matrix Aluminum Nitride Particle Composite as a Low-Thermal-Expansion Thermal Conductor
Authors: Lai Shy-Wen , Chung D. D. L. 
Published: March 2011

AbstractAluminum-matrix composites containing AIN or SiC particles were fabricated by vacuum infiltration of liquid aluminum into a porous particulate preform under an argon pressure of up to 41 MPa. Al/AIN was superior to Al/SiC in thermal conductivity. At 59 vol.% AIN, Al/AlN had a thermal conductivity of 157 W/m. °C and a thermal expansion coefficient of 9.8 × 10−-6°C−1 (35–100 °C). Al/AlN had similar tensile strength and higher ductility compared to Al/SiC of a similar reinforcement volume fraction at room temperature, but exhibited higher tensile strength and higher ductility at 300–400°C. The ductility of Al/AlN increased with increasing temperature from 22 to 400°C, while that of Al/SiC did not change with temperature. The superior high temperature resistance of Al/AlN is attributed to the lack of a reaction between Al and AIN, in contrast to the reaction between Al and SiC in AI/SiC.
A Damage Integral Based Analysis and Simulation of the Thermal Fatigue of Diebonds
Authors: Lilienfeld David A. , Børgesen Peter , Li Che-Yu 
Published: March 2011

AbstractMicroelectronic packages undergo substantial thermal excursions during processing and often in service. Differences in the thermal expansion of the various components may therefore lead to fatigue of the interconnects. A computer simulation has been developed which is based on a damage integral approach for the modeling of damage and failure in the various bonding layers found throughout such a package. This code should apply equally well to solder die bonds and polymeric or epoxy adhesive layers, assuming that the corresponding crack growth parameters and constitutive relations are known. Using literature values for these properties, predictions have been compared to experimental thermal cycling data for solder die bonds. Consequences for the extrapolation of accelerated test results to service conditions are discussed.
Low Stress, High Resolution Photosensitive Polyimide Based on a BPDA/PDA/6FDAm Copolymer
Authors: Angelopoulos Marie , Gelorme Jeff , Swanson Sally , Labadie Jeff 
Published: March 2011

AbstractA novel series of BPDA/PDA/6FDAm polyimide copolymers have been developed. These materials are more flexible, soluble, and more optically transparent than the homopolymer BPDA/PDA. A negative acting PSPI has been developed based on one of these copolymers. This PSPI exhibits high resolution. 6 μm lines can be delineated in a 19 μm thick film. In addition, the PSPI exhibits high performance mechanical/physical properties such as a low CTE, low stress, and high elongation at break.
Micro-ATR-IR as a Probe of BCB Layers for MCM-D/L Applications
Authors: Mohler C. E. , Strandjord A. J. G. , Castillo D. W. , Stachowiak M. R. , Heistand R. H. , Garrou P. E. , Tessier T. G. 
Published: March 2011

AbstractTo lower the cost of multichip module packaging, hybridized substrate technologies have recently been reported which blend the desirable aspects of D and L fabrication (MCM-D/L). High performance dielectrics such as Cyclotene™3022 and photosensitive BCB have been shown to be compatible with laminate substrates used in MCM-DIL, however the cure levels of the dielectric on the laminates must be known for optimum processing.In this paper, the capability of attenuated reflection IR microscopy (micro-ATR-IR) to probe thin films of BCB polymers is demonstrated. This technique enables the polymer layer to be probed regardless of the characteristics of the substrate. Cure levels of both Cyclotene™ 3022 and photodefinable BCB polymer films are obtained with micro-ATR-IR on both silicon and laminate substrate. Micro-ATR-IR is also used to probe a rapid thermal cure of Cyclotene Tm 3022 and photodefinable BCB layers on copper-clad polyimide laminate; these measurements cannot be made with transmission IR due to the high reflectivity of the substrate.
Optoelectronic Packaging for Computer and Communication Systems
Authors: Lockwood H. F. , Armiento C. A. 
Published: March 2011

AbstractThe principal driver behind advanced hardware development in the communications and computer industries can be reduced to an optimal set of parameters related to performance, cost and reliability. High performance systems typically have high functional density. For example, the continuing trend of VLSI is toward reduced feature size, increased wiring density and larger chip size to achieve increasingly higher levels of on-chip functionality. At some point in the cost structure, however, the single chip solution is no longer viable, and monolithic integration gives way to hybrid integration. In this respect, the multichip module fills a void in the packaging/ integration hierarchy between the ever-larger single chip and the printed wiring board.An analogous situation is emerging in optoelectronics. The single chip package with its relatively low system functionality and high cost is giving way to the multi-technology module that integrates optical and electronic functions within a single package. One of the most interesting approaches to the multi-technology module uses a silicon substrate as the platform for hybrid integration of electronics and optoelectronics. It will be argued that this “silicon waferboard” approach is the cost-effective route to manufacturability of high-performance modules for communications and computer systems. Enhanced reliability follows from applying standard IC processing technology at the platform level in the packaging hierarchy.
X-Ray Absorption Study of Ti and Cr Reactions with Triazine and Polyimide
Authors: Konstadinidis K. , Opila R. L. , Marcus M. A. , Short K. , White A. E. , Ibidunni A. O. , Davenport A. , Isaacs H. 
Published: March 2011

AbstractIn this paper we present results on the use of x-ray absorption spectroscopy and in particular extended x-ray absorption fine structure (EXAFS) to study non-destructively buried interfaces between polymers and metals. In particular we study the interaction between isolated metal atoms (Ti or Cr) and the surrounding polymer matrix (polyimide or triazine). The metal atoms have been introduced into the polymer matrix using ion-implantation. We find that Cr forms a π complex with the aromatic structures of polyimide and triazine in agreement with model compound and XPS data. Ti on the other hand seems to form Ti-O-C bonds with both polymers.
Interfacial Debonding in PWBs
Authors: Li Junhui , Pecht Michael 
Published: March 2011

AbstractGlass fiber reinforced epoxy laminates have been widely applied in the electronic packaging industry as multilayer printed wiring boards (PWBs). Previous investigations indicate that, the electric insulation between printed through hole (PTH) and conductive lines can be lost if the boards are subjected to certain environmental conditions [1,2,3]. The insulation breakdown is caused by copper filament formation along the glass fibers once the filament bridges any two nearby circuittraces, such as a PTH and a power plane, or between two PTHs. The conductive filament formation is a two step process: path formation and electrochemical reaction. The path formation is caused by degradation of the glass-epoxy interface, which provides the copper ion migration path for the second step. Humidity and temperature are the key factors leading to interfacial degradation. Usually, humidity is of more concern because water absorption helps the path formation. Among board materials, epoxy resin, as the matrix material, is more susceptive to moisture absorption than glass fiber or copper [3,4]. Operating temperature that changes the degree of moisture absorption [5,6], and thermal cycling that enhances water absorption, and stress induced from thermal-mismatches [7], are also considered as the important factors to the interface degradation.Epoxy/glass interfacial debonding can be introduced near PTHs by thermal cycling [8]. The interfacial debonding between glass fibers and the epoxy matrix near PTHs accelerates the electromigration process. In order to study the interfacial debonding mechanisms, thermal cycling tests of PWBs were conducted and the dynamic process of interfacial debonding was characterized using environmental scanning electron microscope (ESEM). This paper presents the experimental results with discussion of the possible interfacial debonding mechanisms.
Benchmark of Surface Mount Autoclave Reliability Performance
Authors: Savage Timothy Scott , Masteller Melissa , Burkhard Dave , Lau S. C. 
Published: March 2011

AbstractThis benchmark study examined the effect of four different backmetal/ leadframe schemes on the time to failure from autoclave testing for surface mount, small signal transistors in the SC59 package configuration. The four schemes examined included die with Au backmetal bonded to a Cu plated Alloy 42 leadframe, Au backmetal bonded to a Ag striped, Ni plated, Cu plated alloy 42 leadframe, Au backmetal with a thin, permeable Ni layer bonded to a Ag striped, Ni plated Cu leadframe and V/Ni/AuGe/Au backmetal bonded to a Cu leadframe. Devices with AuSi eutectic bonded directly to the Cu plated Alloy 42 leadframe separated between the Si die and the AuSi eutectic after 240 hours of autoclave testing which produced VCESAT failures. Identical devices bonded to Ag striped, Ni plated, Cu plated Alloy 42 leadframes had the same failure mechanism after 624 hours of autoclave testing. Adding a permeable Ni layer to the AuSi eutectic structure and bonding to a Ag striped, Ni plated Cu leadframe increased the lifetime to 744 hours but still produced the same failure mechanism. Devices using a V/Ni/AuGeJAu bonded to a Cu leadframe remained electrically good and physically intact after 864 hours of autoclave testing. These results indicate the use of leadframe plating and/or backmetal barrier metals is needed in order to produce devices that can withstand extended reliability testing.
Noninvasive Real-Time Evaluation of the Anisotropic Thermal Diffusivity in Thin Polymer Films for Electronics Packaging
Authors: Rogers John A. , Mindas C. , Yang Y. , Nelson K. A. 
Published: March 2011

AbstractWe describe an experimental method capable of evaluating the in- and out-of-plane components of the anisotropic thermal diffusivity in supported and unsupported thin polymer films. The technique is used to quantify the in-plane thermal diffusivity in films of PMDA/ODA (Dupont's P12545), BTDA/ODA/MPD (Dupont's P12555), BPDA/PPD (Dupont's P12611), BCB (Dow's Cyclotene 3022) and HFDA-APBP (Amoco's UD4212) with thicknesses in the 1–10 micron range.
Raman and Photoluminescence Characterization of FIB Patterned AIGaAs/GaAs Multiple Quantum Wells
Authors: Choo Ahn Goo , Cao Xuelong. , Tlali Spirit , Jackson Howard E. , Chen Peter , Steckl Andrew J. , Boyd Joseph T. 
Published: March 2011

AbstractRaman and photoluminescence (PL) spectra have been used to characterize A10.3Ga0.7As/GaAs multiple quantum well (MQW) structures that have been patterned by focused ion beam (FIB) implantation followed by rapid thermal annealing (RTA). Microprobe Raman scattering is used to identify the appropriate RTA and FIB implantation conditions that provide for removal of implantation-induced damage and for compositional intermixing. FIB patterned wire-like structures are characterized by spatially resolved PL spectra.
Photoreflectance Characterization of InGaAs/GaAs Superlattices Grown on [111]-Oriented Substrates
Authors: Rodrigues R. G. , Yang K. , Schowalter L. J. , Borrego J. M. 
Published: March 2011

AbstractWe report the results of a photoreflectance (PR) study of InGaAs/GaAs strained-layer quantum wells and superlattices (SLSs) grown by MBE on [111]B GaAs substrates. Under our measurement conditions, the PR spectra display features we can relate to the bandgaps of both materials and to optical transitions in the quantum structures. Using the photovoltaic effect to vary the surface electric field of our i-n+ and p+-i-n+ samples in a strictly contactless manner, we find optical transitions red-shifting with increasing intensity of illumination from a CW HeNe laser in [111]-grown structures, a well known effect which can be attributed to the straingenerated electric field (SGEF) present in these structures. We also find experimental support for the predicted effectiveness of free-carriers in screening the SGEF and thereby originating highly non-linear absorption.
Photoreflectance Characterization of InGaAs Lattice Matched to InP
Authors: Bellani V. , Amiotti M. , Geddo M. , Guizzetti G. , Landgren G. 
Published: March 2011

AbstractWe measured photoreflectance (PR) spectra at different temperatures between 80 and 300 K, and optical absorption (OA) at 3 K on MOVPE grown Inl-xGaxAs nearly lattice-matched to InP. x-ray diffraction measurements gave a lattice mismatch δa/ao = -0.9.10−3 between ternary alloy and InP, corresponding to × = 0.485. We obtained the energy gap dependence on T from PR spectra. The blue shift of the gap was accounted for in terms of compositional difference with respect to the perfectly lattice matched alloy (× = 0.472), and elastic strain; moreover PR and OA showed evidence of the valence bands splitting at k = 0 due to interfacial strain, in fine agreement with theory.
Room Temperature Measurement of Photoluminescence Spectra of Semiconductors Using an Ft-Raman Spectrophotometer
Authors: Webb J. D. , Dunlavy D. J. , Ciszek T. , Ahrenkiel R. K. , Wanlass M. W. , Noufi R. , Vernon S. M. 
Published: March 2011

AbstractThis paper demonstrates the utility of a Fourier transform (FT) Raman spectrophotometer in obtaining the room-temperature photoluminescence (PL) spectra of semiconductors used in photovoltaic and electro-optical devices. Sample types analyzed by FT-PL spectroscopy included bulk silicon and films of copper indium diselenide (CuInSej), gallium indium arsenide (GaInAs), indium phosphide arsenide, (InPAs), and gallium arsenide-germanium alloy (GaAsGe) on various substrates. The FTIR-PL technique exhibits advantages in speed, sensitivity, and freedom from stray light over conventional dispersive methods, and can be used in some cases to characterize complete semiconductor devices as well as component materials at room temperature. Recent innovations that improve the spectral range of the technique and eliminate instrumental spectral artifacts are described.
Application of Ftir Spectroscopy to the Characterization of as-Deposited and Chemical Mechanical Polished (CMP) Electron Cyclotron Resonance (ECR) Plasma Based SiO2 Films
Authors: Desai Mukesh , Carpio Ron , Jairath Rahul , Stell Matt , Tolles Robert 
Published: March 2011

AbstractFTIR spectroscopy has been used to characterize as-deposited and chemical mechanical polished (CMP) electron cyclotron resonance (ECR) plasma based SiOx films. The ECR films were deposited at different O2/SiH4 gas ratios in an attempt to vary the film stochiometry. Transmission and reflectance-absorbance IR spectral data were combined with CMP removal rate information to characterize the SiOx films and their polishing behavior. The asymmetric O-Si-O stretching (ASM) and Si-OH vibrational bands were found to be principal sources of information.
Characterization of Polysilicon Films by Raman Spectroscopy and Transmission Electron Microscopy: a Comparative Study
Authors: Tallant David R. , Headley Thomas J. , Medernach John W. , Geyling Franz 
Published: March 2011

AbstractSamples of chemically-vapor-deposited sub-micrometer-thick films of polysilicon were analyzed by transmission electron microscopy (TEM) in cross-section and by Raman spectroscopy with illumination at their surface. TEM and Raman spectroscopy both find varying amounts of polycrystalline and amorphous silicon in the wafers. Raman spectra obtained using blue, green and red excitation wavelengths to vary the Raman sampling depth are compared with TEM crosssections of these films. Some films have Raman spectra with a band near 497 cm−1, corresponding to numerous nanometer-scale faulted regions in the TEM micrographs.
Characterization of Interfacial Structure of InGaAs/InP Short Period Superlattices by Raman Scattering and High Resolution X-Ray Diffraction
Authors: Mozume Teruo 
Published: March 2011

AbstractThe x-ray diffraction (XRD) of InGaAs/InP short-period superlattices (SPSL's) grown on (001)InP substrates by gas source molecular beam epitaxy (GSMBE) and by gas source migration enhanced epitaxy (GSMEE) shows that the GSMBE grown SPSL is strain free, and that GSMEE grown SPSL's with InGa-P and In-As heterointerfaces have strain-induced zerothorder satellite peak shift consistent with that in simulation results for the InGaAs/InP SPSL with one monolayer of InGaP and InAs inserted in each interface. Partial destruction of the long-range order is confirmed by the observation of the extra diffraction peak in GSMBE grown SPSL and by weak intensity of satellite peaks and nonuniform spacing between satellite peaks in GSMEE grown SPSL's. Raman scattering shows that the strain is accommodated in the interface layer in GSMEE grown samples. A confinement model without interface disorder fits the GaAs LO phonon very well. These results indicate that the local atomic arrangements are tailored by GSMEE, but that long range-order is impaired by the misfit dislocations in GSMEE grown SPSL's and by the exchange between As to P at the interfaces in GSMBE grown SPSL.
Relating Photoresist Etch Characteristics to Langmuir Probe Measurements in an Electron Cyclotron Resonance Source
Authors: Sung K. T. , Juan W. H. , Pang S. W. , Dahimene M. 
Published: March 2011

AbstractIn this work, Langmuir probe measurements were used to characterize a multipolar electron cyclotron resonance (ECR) plasma source. This system has many controllable parameters including microwave power, rf power, gas, pressure, flow rate, and source distance. Both double and triple Langmuir probes were used for the plasma characterization. The results from the Langmuir probe measurements were correlated to the etch characteristics of photoresist. Ion density and photoresist etch rate were found to increase with microwave power but decrease with source distance. However, rf power does not have significant influence on ion density although the photoresist etch rate increases substantially with if power. Ion density first increases then decreases at higher pressure. Maximum ion density occurs at lower pressure for larger distance below the ECR source. Ion density uniformity for an O2 plasma is ±2% across a 16 cm diameter region at 23 cm below the source. For photoresist etched at 10 cm source distance, etch rate uniformity is ±2% for a 15 cm diameter wafer. The results from the Langmuir probe measurements indicate that photoresist etching is enhanced by ion density and ion energy.
Surface Reactivity of Silicon and Germanium in CF4 -O2 Reactive Ion Etching
Authors: Cardinaud Christophe , Campo A. , Turban G. 
Published: March 2011

AbstractReactive ion etching of silicon and germanium in CF4 -O2 was investigated. Above 20% O2 germanium etching is selective with respect to silicon. In agreement with the evolution of the fluorine and oxygen concentration in the plasma and of the etch products formation rate, surface analysis reveals that the growth of a SiOxFy layer slows down the silicon etching whereas the formation of GeOxFy does not inhibit germanium etching. Using a simple kinetic model, the silicon and germanium reactivity and its dependency with respect to the plasma composition are expressed in function of the experimental data. Results suggest that surface composition controls silicon etching, whereas germanium etching depends only on the fluorine flux on the surface.
In Situ Substrate Temperature Measurement During MBE by Band-Edge Reflection Spectroscopy
Authors: Roth J. A. , Lyon T. J. De , Adel M. E. 
Published: March 2011

AbstractThe use of band-edge reflection spectroscopy (BRS) to determine the substrate temperature during MBE is reviewed. Data are presented for Si, GaAs, InP and CdZnTe substrates, and the use of BRS during the growth of ZnTe on Si is demonstrated. We discuss complications that arise due to optical interference in the epitaxial layers, and methods to compensate for the effects of interference are described.
Trapping of Molecular Hydrogen in Porous Silicon and at Si/SiO2 Interfaces and a Possible Reinterpretation of the Pb Center
Authors: Stallinga Peter , Gregorkiewicz T. , Ammerlaan C.A.J. 
Published: March 2011

AbstractMany recent studies of the highlighted problem of visible-range photoluminescence of porous silicon (po-Si) indicate the presence of hydrogen in this material. However, its actual role is not clear with the discussed possibilities ranging from passivation of the surface defects to some form of active participation in the photoluminescence (PL) mechanism itself. At the same time, in several magnetic resonance studies of po-Si the so-called Pb center, originally identified with the <111>-directed silicon broken bond stabilized at Si/SiO2 interfaces, has been reported.Very recently the paramagnetic state of molecular hydrogen in bulk silicon has been identified. The spin-Hamiltonian parameters of the related Si-NL52 EPR spectrum appear to be identical to those of the Pb center. This observation casts severe doubts on the original interpretation of the Pb center while, on the other hand, offering new evidence of a prominent presence of hydrogen molecules both in po-Si and at the Si/SiO2 interface. In this paper the similarities of Si-NL52 and Pb centers are examined in detail, and it is argued that the centers are the same. It is concluded that many features of the Pb center which could not be explained within the broken-bond model can be understood with the interstitial hydrogen molecule model.
Spectroscopic Ellipsometry Characterisation of Thin Film Polysilicon
Authors: Lynch S. , Spinelli L. , Sherlock M. , Barrett J. , Crean G.M. 
Published: March 2011

AbstractPhase modulated Spectroscopic Ellipsometry (SE), in the spectral range from 1.5eV to 4.6eV, was employed to characterise thin film polysilicon (poly-Si) deposited by Low Pressure Chemical Vapour Deposition (LPCVD) on SiO2/Si(100) substrates as a function of process parameters. The LPCVD deposition temperature was varied from 550°C to 620°C for silane pressures ranging from 100mTorr to 230mTorr. A variation in poly-Si microstructure was observed as a function of film depth. The influence of deposition conditions on poly-Si surface morphology was quantified using both atomic force microscopy (AFM) and SE. An increase in the measured Raman TO phonon amplitude was observed for the 620°C sample set as a function of increasing LPCVD process pressure.