Direct write EC single metal layer

摘要

A direct write and laser delete system for making engineering changes in which top surface metal C4 pads each has a small satellite pad connected to it by a short connecting line that is deleted if an engineering change is to be made. Vias connect the satellite pads to a "personality" wiring layer in the module. A top surface grid of line segments allows any C4 pad to be connected to a point outside the chip boundary by means of one or more short direct write lines. There is one global X and Y engineering change grid on respective X and Y thin-film layers and another global X and Y engineering change grid on respective X and Y multi-layer ceramic module layers. All of these varied patterns are connected to lines with each chip pitch boundary where direct write connections can be made, and a grid line can be interrupted by a laser deletion of a top surface metal line.