Abstract: The present concepts include "1:1" uniax (40) with one conductive through-hole per chip connection site, "mirror chip" testing, heat-sink bonding to chips, avoiding contact with conductive cleaved edge of chip, indium solid columns, metal recessed (41) in the through-holes. All of these are subject to preferred materials (UPILEX polyimide) and techniques (U.V. laser ablation, minimum taper of holes).

Abstract: Polymer (preferably polyimide) sheets (10) with laser ablated through-holes plated with metal (20) are used for making electrical conections to specified microcircuits, especially unbumped microchips and Tape Automated Bonding (TAB) articles. Bonding with different melting point materials at opposite ends of the plated holes is disclosed. Preferred polyimides are those derived from polymerisation of 4,4'-biphenyldianhydride and (4,4'-diaminobiphenyl, or 4,4'-diaminobiphenylether, or phylenediamine, preferably p-phenylenediamine).

Abstract: Article and method of making same by laser-ablation-machining of (a) aromatic and/or amorphous polyamide material, or (b) polymeric material having repeating in its polymer backbone aromatic rings and aliphatic chains (with the proviso that the aliphatic chains have at least 4 carbon atoms when the material is a polyester, and preferably in all cases U.V. laser radiation is preferred, preferably at wavelengths greater than 248 nm from a KrF or XeCl excimer laser. The preferred polyamides, polyetheresters, and polyimides have superior machining performance and may be useful for making uniaxially electrically conductive articles by machining holes cleanly through laminar sheets of the preferred polymers, which sheets are subsequently metal plated.

Abstract: An article for tape-automated bonding of integrated circuit microchips comprises a carrier sheet (22) carrying conductive tracks (23) with a tubular metal formation (21) passing through the sheet at the end of each track for connection to a microchip (24). The tubular formations tend to accommodate irregularities in the chip and may contain solder or other metal having a lower melting point than the tubular formation to effect bonding.

Abstract: A sheet laminate of polyimide and amorphous polyamide especially suitable for making anisotropically electrically conductive articles by laser abiation drilling followed by metal plating. Preferred polyimides include those derived from polymerization of 4,4'biphenyldianhydride and 4,4'-diaminobiphenylether or p-phenylenediamine. Preferred amorphous polyamides include those derived from condensation of terephthalic acid with isomers of trimethylhexamethylenediamine.