Abstract: A stepped via is formed in a circuit board. Large holes are punched in a predetermined pattern in two insulating sheets and small holes are punched in the same pattern in another insulating sheet. The holes are dimensioned so that their diameters are larger than the thicknesses of their respective sheets. However, the diameters of the larger holes are less than the combined thickness of all sheets. The sheets are juxtaposed so that the sheet with the smaller holes is between the other sheets and corresponding holes from the respective sheets are aligned. The sheets are pressed together to form an integral substrate. Metallization is applied from one side of the substrate, then metallization is applied to the substrate from the other side.

Abstract: A semiconductor assembly which includes a carrier and a semiconductor die is mounted on a printed wiring board. The die includes a top active surface and a bottom active surface. The two active surfaces are non-coplanar. The carrier is made from layers of a ceramic material. Holes are formed through all but one of the layers. The layers are laminated into an integral substrate, and the substrate is fired. The holes form a cavity into but not through the substrate. The number of layers, lamination pressures, and firing parameters are all adjusted in response to the thickness of the die to insure that the height of cavity walls approximately equals the thickness of the die. Continuous metallization is applied in the cavity and on a top surface of the substrate. The die is bonded in the cavity, and conductive bumps are formed on the die and the metallization.

Abstract: Halogenated hydrocarbons are removed from hydrocarbon solvents for reuse in a butyl rubber process by contacting the halide containing hydrocarbon solvent with alumina at a temperature of at least 20.degree. C. In particular 2-methyl-3-chloropropene-1, 2-methyl-1,2-dibromo-3-chloropropane and tribromo isobutane or mixtures thereof can be removed from a hydrocarbon solvent by the process of this invention. The halide removal is preferably carried out at a temperature of at least 40.degree. C., e.g., 60.degree. C. to 100.degree. C.

Abstract: A package and a method of packaging semiconductor devices, especially in expanded wafer form. The package is formed by sticking an adhesive backed ring to the plastic sheet upon which the expanded wafer is affixed so that the ring surrounds the wafer. The adhesive backed ring holds the plastic sheet securely and protects the surface of the wafer. The package is completed by covering the wafer with a second protective sheet and vacuum sealing in a plastic bag.

Abstract: Methods for producing rubbery polymers are disclosed comprising forming a slurry of such rubbery polymers, preferably butyl rubber prepared from a mixture of a C.sub.4 to C.sub.8 isoolefin and a C.sub.4 to C.sub.10 conjugated mutiolefin in a low temperature reaction zone in the presence of a Friedel-Crafts catalyst and an organic halide diluent, passing that slurry into an overflow passage for transporting the slurry to a recovery system, and injecting a mixture of a hydrocarbon liquid having a boiling point above the boiling point of the organic halide and a polar organic catalyst quenching agent into said overflow passage at a point adjacent to the outlet from the reaction zone in order to prevent continued production of polymer in the overflow passage and to maintain the overflow passage substantially free of agglomerates.

Abstract: A desiccant regeneration system is disclosed which employs polymerization diluent as regeneration medium for monomer recycle desiccant driers in ethylene-alpha olefin copolymerizations and utilizes existing diluent purification systems (i.e., systems employed in polymerization processes for diluent recycle), thereby avoiding separate regeneration facilities, providing high purity regeneration fluid and allowing regeneration at relatively mild temperatures.