In a module for an array of integrated circuit chips, said module comprising a matrix of insulating material having an upper surface with a set of pads for connection of chips thereto with metallization beneath the surface for standard connections between pads connected to said chips, and fan-out chips, and fan-out metallization with fan-out pads surrounding the mounting area of each chip,
- said chips being arranged upon said module in a substantially orthogonal pattern upon said upper surface with engineering change pads deposited upon said upper surface adjacent to said fan-out areas, with parallel an orthogonal engineering change lines,
- the improvement comprising embedding of said engineering change lines aligned within said matrix of said module beneath said upper surface with each of said engineering change lines in a predetermined orientation including a plurality of periodically spaced breaks along the length thereof with connection vias extending upwardly to said surface in parallel from the ends of each of said breaks to an engineering change pad in the form of a link,
- whereby each of said links can be connected to one of said fan-out pads by means of fly-wires and said link can be severed into two separate segments to provide a flexible wiring system with minimal inductive coupling, and minimal crossovers in the module employed for engineering change purposes, connections being provided between an engineering change line in the x direction and an engineering change line in the y direction by means of a fly-wire, said fly-wire being short relative to said engineering change lines and on the order of less than one centimeter in length.