Engineering Change Wiring System for Semiconductor Package
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
In large-scale integrated circuit packages, it is known to provide engineering change pads associated with I/O pads on solder-bonded devices mounted on the substrate which provide a means for altering the internal circuitry of the substrate. This concept is described in more detail in 11, 2]. In use, discrete wires are ultrasonically bonded to the engineering change pads which provide additional or alternate wiring capable of connecting the various I/O pads of the devices mounted on the substrate. In more sophisticated packages, this wiring scheme can cause problems because of the excessive cross-talk, uncontrolled characteristic impedance, and propagation velocity associated with the wiring on the surface of the substrate.