Substrate (building)

Abstract: A distributed constant circuit board including a ceramic substrate, and at least one conductor pattern which is carried by the ceramic substrate and which forms a resonance circuit, an inductor, a capacitor or strip transmission line. The conductor pattern has an electrically conductive composition whose major component is selected from the group consisting of Ag, Au and Cu, and which has a sheet resistivity not higher than 10 mΩ per square. The conductor is formed by co-firing with the ceramic substrate, so that the conductor pattern is incorporated in the substrate. The ceramic substrate is formed principally of a ceramic composition which gives the resonance circuit a resonance frequency whose temperature coefficient is held within a range between -30 ppm/° C. and +100 ppm/° C.

Abstract: Desiccation cracking is ubiquitous in many materials of practical importance, such as in mud, clay soil, pavement, and concrete, and understanding its dynamics and formation is essential for developing an effective means of its prevention or utilization. We report on a phenomenological investigation aimed at delineating the effect of a coarse-textured substrate on the cracking dynamics and morphology of an overlying kaolinite clay layer. Drying experiments were carried out using a glass container mounted on a digital balance, packed with a thin layer of kaolinite clay overlying seven types of sand that differed in their particle size distributions. An automatic imaging system recorded the dynamics of cracking at the evaporating surface. Dynamic analysis suggests a decreased duration of cracking with increased substrate particle size and substrate-independent initial crack propagation. Analysis of the cracking morphology indicates a decreased crack density and larger crack length, and an increased crack width mean and standard deviation with increased substrate particle size. Scanning electron microscopy results, used to study the extent of cracking over various length scales, indicate that only macroscopic cracks formed on the kaolinite clay surface. Fractal and density correlation function analysis of the final crack networks indicate the dependency of the fractal dimension on the substrate particle size, and a crossover length scale ξ that separates the fractal regime from the uniform crack density regime. For length scales greater than ξ, the density correlation function asymptotically approaches the crack density at the surface of the clay.

Abstract: For use as a substrate for a heat generating microelectronic integrated circuit, a ceramic panel is provided having small thickness in comparison to its length and breadth, having on at least the surface opposite the one bearing the microelectronic integrated circuit, a layer of heat conductive metal and having a plurality of closely spaced, small cross section extensions of the heat conductive metal layer extending into the ceramic material to a depth of at least about one fifth of its thickness. The substrate is particularly useful for the mounting of hybrid microelectronic circuits to improve the heat dissipation capability of the ceramic substrate.

Abstract: A method of fabricating ceramic parts is disclosed using a laser deposition process to produce highly dense ceramic parts A metal substrate is preferably used and ceramic powder deposited in layers on the substrate, while varying the power of the laser beam to bond the layers together without cracking the substrate or causing a plasma reaction in the ceramic powder Dense structures which are about 96% to about 100% ceramic can be produced A part can be graded using different types and mixtures of ceramic powders to produce the part of a desired composition