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Circuit Personalization on Polyimide

IP.com Disclosure Number: IPCOM000045146D
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Fern, RE: AUTHOR [+3]

Abstract

Localized line deletion for circuit personalization or defect repair is required for chip and high-density package technologies. The different levels of thin film circuitry are separated by an insulating layer. A material for this insulating layer is polyimide.

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Circuit Personalization on Polyimide

Localized line deletion for circuit personalization or defect repair is required for chip and high-density package technologies. The different levels of thin film circuitry are separated by an insulating layer. A material for this insulating layer is polyimide.

A technique is described herein using a combination of optical spectroscopic measurement, selected laser pulse width, and laser pulse energy to solve the problem of thermal degradation of polyimide during laser deletion.

Pertinent parameters of the polyimide include: (1) degrades thermally at a temperature above 450 degrees C; and (2) different optical properties depending on the curing temperature. For successful laser deletion the optimum wavelength, pulse width, and pulse energy have to be carefully selected.

It is essential for line deletion on polyimide RC 5878 (Trademark of E.I. du Pont de Nemours & Co.) to use a laser with wavelengths above 0.6 micron. Direct absorption of the laser light in the polyimide makes damage possible. Further, it is important to minimize the heat conducted to the polyimide by the metal. Thus, pulse width of the order of 10-30 nanoseconds is needed.

A configuration has been used with: a nitrogen pumped dye laser, a pulse width 8 nanoseconds, pulse energy of 10 micro-joules, and a wavelength of 0.6 micron to delete Cr-Cu-Ni lines, 15 microns wide and 4 microns thick on RC 5878 (Trademark of E.I. du Pont de Nemours & Co.) polyimides. This...