Abstract: Electronic device packaging structures useful for electrically interconnecting an electronic device to a substrate. The structure contains at least two metallization layers with dielectric layers between adjacent to metallization layers. The dielectric layers can have variable thickness. Beam leads can project inwardly in cantilevered fashion over a central aperture through the dielectric layers. The inner ends of the beam leads lie substantially in one plane and can be bonded to contact pads on integrated circuit electronic devices. Beam leads can project outwardly from the metallization layers over outer edges of the dielectric layers for bonding to contact pads on a substrate. Signal leads on metallization layers can be symmetrically arranged between ground and voltage leads to provide optimal impedance properties. These structures are useful for tape automated bonding applications.

Abstract: Single-stage thermolysis of C.sub.8 and C.sub.9 aromatics at temperatures in excess of 900.degree. C. and pressures of less than 0.2 torr or in the presence of steam in excess of 800.degree. C., in the absence of catalysts yields styrene and/or p-methylstyrene in high yields, providing a process for the conversion of xylenes and p-ethyltoluene to preferred styrene monomers.