Browse Prior Art Database

Localized Heating of Chip Bonding Pad

IP.com Disclosure Number: IPCOM000092775D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Chiou, C: AUTHOR [+4]

Abstract

Selective bonding to, removal from, and replacement of semiconductor chip devices on a dielectric substrate without affecting neighboring devices is accomplished by localized heating of the individual pad, bonding a chip device to the substrate.

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Localized Heating of Chip Bonding Pad

Selective bonding to, removal from, and replacement of semiconductor chip devices on a dielectric substrate without affecting neighboring devices is accomplished by localized heating of the individual pad, bonding a chip device to the substrate.

The localized heating is effected by the use of the bonding pad as a resistance heating strip or by the use of a buried heater surrounding such pad. In any high-density packaging array, the ability to heat, bond or remove a single unit without affecting neighboring units is a distinct advantage.

In A, one such array includes an insulating substrate 11 supporting a plurality of silicon semiconductor chip devices 12. Spaced bonding pads 13, typically
.090" x .090" at .250" center-to-center, are formed by evaporating through mask metallized coatings of chromium and then gold on the surface of the substrate to a thickness of one and five microns respectively. A chip device 12 is placed over each pad 13 and a pressure of 400 grams is applied to the top surface of each device. All devices 12 and the entire substrate are heated to a temperature over 370 Degrees C for a period of time sufficient to initially, simultaneously bond all devices 12 to the substrate.

To selectively remove and replace a given device 12, current is applied from source 14 to the pad 13 upon contact of tungsten probes 15 to terminal areas 16. In this instance, the pad 13 acts as a resistance eating strip, producing eno...