Browse Prior Art Database

Engineering Change Wiring System for Semiconductor Package

IP.com Disclosure Number: IPCOM000051577D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Davidson, EE: AUTHOR [+3]

Abstract

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.

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Engineering Change Wiring System for Semiconductor Package

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.

In this wiring scheme, the wires 10 used to join one or more engineering change pads 12 on multilayer ceramic substrate 14 are coaxial wires. The wire 10 can be made by plating a conventional wire insulated with a polyimide or TEFLON* coating with lead or other conductive metals. As shown in the figure, the wires 10 are arranged in channels which are supported on a surface layer of molybdenum 16 with a surface gold plating. The molybdenum layer 16 is connected to ground by vias 18. The coaxial engineering change wires 10 are placed on the metallized channel 16, and both ends are bonded to the proper engineering change pads 12. The ground connection for the shields is provided by reflow...