Recent Advances in Low CTE and High Density System-on-a-Package (SOP) Substrate with Thin Film Component Integration

The Packaging Research Center has been developing next generation system-on-a-package (SOP) technology with digital, RF, optical, and sensor functions integrated in a single package/module. The goal of this effort is to develop a platform substrate technology providing very high wiring density and embedded thin film passive and active components using PWB compatible materials and processes. The latest SOP baseline process test vehicle has been fabricated on novel Si-matched CTE, high modulus C-SiC composite core substrates using 10mum thick BCB dielectric films with loss tangent of 0.0008 and dielectric constant of 2.65. A semi-additive plating process has been developed for multilayer microvia build-up using BCB without the use of any vacuum deposition or polishing/CMP processes. PWB and package substrate compatible processes such as plasma surface treatment/desmear and electroless/electrolytic pulse reverse plating was used. The smallest line width and space demonstrated in this paper is 6mum with microvia diameters in the 15-30mum range. This build-up process has also been developed on medium CTE organic laminates including MCL-E-679F from Hitachi Chemical and PTFE laminates with Cu-Invar-Cu core. Embedded decoupling capacitors with capacitance density of >500nF/cm2 have been integrated into the build-up layers using sol-gel synthesized BaTiO3 thin films (200-300nm film thickness) deposited on copper foils and integrated using vacuum lamination and subtractive etch processes. Thin metal alloy resistor films have been integrated into the SOP substrate using two methods: (a) NiCrAlSi thin films (25ohms per square) deposited on copper foils (Gould Electronics) laminated on the build-up layers and two step etch process for resistor definition, and (b) electroless plated Ni-W-P thin films (70 ohms to few Kohms per square) on the BCB dielectric by plasma surface treatment and activation. The electrical design and build-up layer structure along- - with key materials and processes used in the fabrication of the SOP4 test vehicle were presented in this paper. Initial results from the high density wiring and embedded thin film components were also presented. The focus of this paper is on integration of materials, processes and structures in a single package substrate for system-on-a-package (SOP) implementation

The standard enthalpy and entropy of formation of Rh2O3 - A third-law optimization

The standard Gibbs energy of formation of Rh203 at high temperature has been determined recently with high precision. The new data are significantly different from those given in thermodynamic compilations.Accurate values for enthalpy and entropy of formation at 298.15 K could not be evaluated from the new data,because reliable values for heat capacity of Rh2O3 were not available. In this article, a new measurement of the high temperature heat capacity of Rh2O3 using differential scanning calorimetry (DSC) is presented.The new values for heat capacity also differ significantly from those given in compilations. The information on heat capacity is coupled with standard Gibbs energy of formation to evaluate values for standard enthalpy and entropy of formation at 289.15 K using a multivariate analysis. The results suggest a major revision in thermodynamic data for Rh2O3. For example, it is recommended that the standard entropy of Rh203 at 298.15 K be changed from 106.27 J mol-' K-'given in the compilations of Barin and Knacke et al. to 75.69 J mol-' K". The recommended revision in the standard enthalpy of formation is from -355.64 kJ mol-'to -405.53 kJ mol".

Crystal Structure, Thermal Expansion and ElectricaH Conductivity of Yo.sCao.2Fel-x Mnx03+o (0 < x < 1.0)

The crystal structure, thennal expansion and electrical conductivity of the solid solutions YOgCao.2Fel-x MnxOJ+c5 (0 ~ x ~ 1.0) were investigated. All compositions had the GdFeOrtype orthorhombic perovskite structure with trace amounts of a second phase present in case of x = 0.8 and 1.0. The lattice parameters were detennined at room tempe'rature by using X-ray powder diffraction (XRPD). The pseudocubic lattice constant decreased with increasing x. The average I inear thermal expansion coefficient (anv) in the temperature range from 673 to 973 K showed negligible change with x up to x = 0.4. The thennal expansion curve for x = I had a slope approaching zero in the temperature range from 648 to 948 K. The calculated activation energy values for electrical conduction indicate that conduction occurs primarily by the small polaron hopping mechanism. The drastic drop in electrical conductivity for a small addition of Mn (0 ~ x ~ 0.2) is caused by the preferential fonnation of Mn4t ion~ (rather than Fe4 +) which act as carrier traps. This continues till the charge compensation for the divalent ions on the A-site is complete. The results indicate that with further increase in manganese content (beyond x =0.4) in the solid solutions, there is an increase in exc :::ss oxygen and consequently, a small increase in Mn'll il>I1~, which are charge compensated by the formation of cation vancancies.

Activity of TiO2 in the System ZrO2-TiO2 and Gibbs Energy of Formation of ZrTiO4

The activity of Ti02 in single and two··phase regions of ihe system ZrOrTi02 has heen measured lIsing solid state cells based on yttria··doped tho ria (YDT) as the solid electrolyte at 1373 K. The cells used can be represented as: Pt, Tio.07PtO.Y3 + Zrj.,Tix0 2 / YDT / Ti02 + Tio.07Pto.93, Pt Pt, Tio.07Pto.93 + ZrJ.xTix02 + ZrTi04 / YDT / Ti02+ Tio.07PtO.93, Pt In each cell the composition of Pt-Ti alloy was identical at hoth electrodes. The emf of the cell is therefore directly related to the activity of Ti02 in oxide phase or oxide phase mixture: aTiO~ :;: cxp (-4FE/RT). The activity coefficient of Ti02 in th~ zirconia-rich solid solution with monoclinic structure (CUl2 2" XTi02 2" 0) can be expressed as:In the zirconia-rich solid solution with tetragonal structure (0.085 2" X ri02 2" 0.03), the activity coefficient is given by:In YTi02 (± 0.012) = 2.354 (1-XTiO? )2 +0.064 The standard Gibbs energy of formation of ZrTi04 is -5650 (± 200) J/mol at 1373 K .

Relation between Local Structure and Glass Forming Ability of Liquid Alloys

An attempt has been made to describe the glass forming ability (GFA) of liquid alloys, using the concepts of the short range order (SRO) and middle range order (MRO) characterizing the liquid structure.A new approach to obtain good GFA of liquid alloys is based on the following four main factors: (1) formation of new SRO and competitive correlation with two or more kinds of SROs for crystallization, (2) stabilization of dense random packing by interaction between different types of SRO, (3) formation of stable cluster (SC) or middle range order (MRO) by harmonious coupling of SROs, and (4) difference between SRO characterizing the liquid structure and the near-neighbor environment in the corresponding equilibrium crystalline phases. The atomic volume mismatch estimated from the cube of the atomic radius was found to be a close relation with the minimum solute concentration for glass formation. This empirical guideline enables us to provide the optimum solute concentration for good GFA in some ternary alloys. Model structures, denoted by Bernal type and the Chemical Order type, were again tested in the novel description for the glass structure as a function of solute concentration. We illustrated the related energetics of the completion between crystal embryo and different types of SRO. Recent systematic measurements also provide that thermal diffusivity of alloys in the liquid state may be a good indicator of their GFA.

Soil and Groundwater Pollution from Agricultural Activities

This book introduces the major agricultural activities in India and their impact on soil and groundwater. It lists the basic aspects of agricultural activities and introduces soil properties, classification and processes, and groundwater characteristics, movement, and recharge aspects. It further discusses soil and groundwater pollution from various sources, impacts of irrigation, drainage, fertilizer, and pesticide. Finally, the book dwells upon conservation and management of groundwater and soil.

Thermodynamic Data for Mn3O4, Mn2O3 and MnO2

Thermodynamic properties of Mn3O4, Mn2O3 and MnO2 are reassessed based on new measurements and selected data from the literature. Data for these oxides are available in most thermodynamics compilations based on older calorimetric measurements on heat capacity and enthalpy of formation, and high-temperature decomposition studies. The older heat capacity measurements did not extend below 50 K. Recent measurements have extended the low temperature limit to 5 K. A reassessment of thermodynamic data was therefore undertaken, supplemented by new measurements on high temperature heat capacity of Mn3O4 and oxygen chemical potential for the oxidation of MnO1-x, Mn3O4, and Mn2O3 to their respective higher oxides using an advanced version of solid-state electrochemical cell incorporating a buffer electrode. Because of the high accuracy now achievable with solid-state electrochemical cells, phase-equilibrium calorimetry involving the ``third-law'' analysis has emerged as a competing tool to solution and combustion calorimetry for determining the standard enthalpy of formation at 298.15 K. The refined thermodynamic data for the oxides are presented in tabular form at regular intervals of temperature.

BIOCARDS AND LEVEL OF ABSTRACTION

Biocards are formal descriptions of biological phenomena and their underlying functional principles. They are used in bioinspired design to document search results and to communicate the findings for use in the further design process. The present study explored the effect of abstraction level used in biocards. This was done in two workshops conducted with design students in Denmark and India. Students were given a design assignment and instructions for how to perform the BID ideation work. Half of the students were given biocards with abstract descriptions while the other half got biocards with concrete descriptions. The novelty of found solutions was evaluated by the students by rating novelty of each solution on a scale from 1 to 5. Mean values for abstract descriptions were 0,3 higher than for concrete descriptions indicating that more innovative solutions were found when students used biocards with abstract descriptions compared to concrete descriptions. The difference in mean value is significant with a confidence level better than 1%. It seems likely that more abstract descriptions in biocards helps avoiding design fixation in biomimetic design work.