ALBERT

Notes: This paper addresses materials and processes for printed wiring board compatible embedded capacitors using polymer/ceramic nanocomposites and hydrothermal barium titanate. Polymers allow low temperature fabrication appropriate to the board (MCM-L) technology. The lower dielectric constants of the commercially available polymers can be greatly compensated by incorporating higher permittivity ceramic fillers. Materials requirements for higher capacitance density (〉30?nF/cm2) have been addressed through implementation of a novel low-temperature processable hydrothermal barium titanate film on a patterned titanium foil laminated to the PWB. Application of hydrothermal grown barium titanate is currently being evaluated using a multi-layer system-on-package demonstration.

Notes: Abstract Integral passive is an emerging technology which is currently perceived as a possible alternative to the discrete passive technology in fulfilling the next generation packaging needs. Although discrete surface mount passive components (resistors, capacitors, and inductors) have been well characterized, the development of integral passive components suitable for co-integration on the board level is relatively recent. Since in some applications the number of passive components can exceed the number and the area of IC chips on a circuit board or in a package, such integration of passive components would be necessary to substantially eliminate part count and reduce device area. To address these issues, integration technology for passive elements in the same manner as for transistors is necessary. In addition, the fabrication sequence of all integral passive components should be mutually compatible for co-integration on the same substrate. In this paper, materials and fabrication issues for passive elements such as resistors (R), capacitors (C), and inductors (L) and the feasibility of integration of these fabricated passive components on glass substrates have been addressed. An active filter circuit has been selected for a case study for R, L, and C co-integration. This passive module contains eleven resistors, four capacitors, and four inductors, and is fabricated using MCM-D (multichip module-deposited) compatible processes. A variety of materials appropriate for fabrication of integral passives in a mutually compatible fashion were investigated, including chromium and nickel-chromium resistors, composites of high dielectric constant materials in epoxies for capacitor dielectrics, and composites of magnetic ferrite particles in polyimides for inductor core and shielding. The fabricated devices showed good agreement between the design values and the corresponding measured values. It is anticipated that some of these materials and fabrication processes can be implemented for the MCM-L (multichip module-laminate) compatible packaging. © 2000 Kluwer Academic Publishers

Notes: Abstract Integral passives are becoming increasingly important in realizing next generation electronics industry needs through gradual replacement of discretes. The need for integral passives emerges from the increasing consumer demand for product miniaturization thus requiring components to be smaller and packaging to be space efficient. In this paper, the feasibility of integration of polymer/ceramic thin film (∼5 μm thick) capacitors (C) with other passive components such as resistors (R) and inductors (L) has been discussed. An integrated RC network requiring relatively large capacitance and resistance is selected as a model for co-integration of R and C components using low temperature PWB compatible fabrication processes. This test vehicle is a subset of a large electrical circuit of a functional medical device. In order to produce higher capacitance density and reduce in-plane device area, multi-layer (currently two-layer) capacitors are stacked in the thickness direction. A commercially available Ohmega-Ply resistor/conductor material is selected for integral resistors. Resistors were fabricated using a multi-step lithography process with the utilization of two separate masks. Bottom copper electrodes for capacitors were also defined during the resistor fabrication process. Photodefinable epoxies filled with a high permittivity ceramic powder were used for fabrication of thin film capacitors. Epoxy and ceramic powders were mixed in the required proportion and blended using a high shear apparatus. The coating solution was homogenized in a roll miller for 3 to 5 days prior to casting in order to prevent settling of the higher density ceramic particles. Capacitors were fabricated by spin-coating on the sub-etched copper electrodes. The deposited dielectric layers were dried, exposed with UV radiation, patterned, and thermally cured. Top capacitor electrodes (copper) were deposited using a metal or an e-beam evaporator. The electrodes were patterned using the standard photolithography processes. Selected good samples were used for depositing the second capacitor layer. The RC network is extended to incorporate electroplated polymer/ferrite core micro-inductors through the fabrication of an industry prototype low pass RLC filter. Meniscus coating was evaluated for large area manufacturing with high process yield. A capacitance density of ∼3 nF cm−2 was obtained on a single layer capacitor with ∼6 μm thick films. The capacitance density was increased to ∼6 nF cm−2 with the two-layer deposition process. The capacitors were relatively stable up to a frequency range of 120 Hz to 100 KHz. Meniscus coating was qualified to be a viable manufacturable method for depositing polymer/ceramic capacitors on large area (300mm x 300mm) PWB substrates. Dielectric constant values in the range of 3.5 to 35 with increase in filler loading up to 45 vol% were achieved in the epoxy nanocomposite system where the dielectric constant of the host polymer was limited to ∼3.5. Higher dielectric constant polymers are required to meet the increasingly higher capacitance needs for the next generation electronics packaging. Possible avenues for achieving higher capacitance density in polymer/ceramic nanocomposite system have been discussed.

Notes: Abstract In this paper, we propose a novel test technique for fault detection and automated fault diagnosis using pole/zero analysis of embedded integrated passives. For performing pole/zero analysis, an ensemble of circuits obtained by perturbing the circuit under test parameters using their known statistical distributions is generated. From knowledge of the passive circuit specifications, the poles and zeros of every such circuit are extracted and pass and fail regions for the critical poles and zeros are computed in the real-imaginary plane. The proposed test technique uses a region-matching algorithm to detect faults and perform automated diagnosis of catastrophic and parametric faults using frequency domain 2-port measurements. A practical example is presented in order to verify the proposed pole/zero analysis using the fabricated embedded RC device.

Notes: Abstract The morphology of the micro-deformation and fracture processes that occur in the neighbourhood of a notch prior to macroscopic crack growth were determined by a variety of microscopic techniques. The first micro-event that was observed in all instances was the formation of crack-like pores. The shape of the porous zone could not be deduced from existing yield criteria. In thick sections the porous zone transformed to a fibrillated region and in thin films the porous zone tends to transform into a continuous oriented zone. Fibril fracture consisted of a slow process of thinning by shear followed by a rapid rupture. The above micro-events precede macroscopic crack growth in polyethylene.

Notes: Effect of temperature on the electrical conductivity of PVC-copper composites has been studied. The temperature coefficient of dc resistivity of composites with fillers containing negligible oxide content in the range of 77-303 K is positive, indicating metallic-type conduction. The temperature coefficient of dc resistivity of composites with fillers containing intermediate level of oxide at higher temperatures is negative, indicating a semiconducting behavior. Plots of log conductivity versus log frequency for composites in the insulating region show the hopping-type conduction.