Browse Prior Art Database

Segmented Stripe Devices

IP.com Disclosure Number: IPCOM000073464D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Ainslie, NG: AUTHOR [+3]

Abstract

It is known that certain solutes, e.g., Cu, when added to aluminum increase the electromigration resistance or lifetime. However, open circuit failures as well as short circuit failures resulting from mass pile-up and consequent internal extrusion to adjacent conductors, have been found to occur in areas of solute depletion. Short segments of stripes have longer lifetimes than long segment stripes. The length dependence is related to a finding that solute is depleted from regions upstream and increases in regions downstream in the electron flow.

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Segmented Stripe Devices

It is known that certain solutes, e.g., Cu, when added to aluminum increase the electromigration resistance or lifetime. However, open circuit failures as well as short circuit failures resulting from mass pile-up and consequent internal extrusion to adjacent conductors, have been found to occur in areas of solute depletion. Short segments of stripes have longer lifetimes than long segment stripes. The length dependence is related to a finding that solute is depleted from regions upstream and increases in regions downstream in the electron flow.

Replacement of long conductors by short segmented conductors will increase electromigration resistance by many orders of magnitude. Since failures have been found in regions of solute depletion, this will increase electromigration resistance by keeping solute content sufficiently high throughout the volume of the conductor while not allowing excessive solute pile-up downstream of the electron flow.

Assuming a stripe of length X is powered by a current density j which is a pulsating DC signal as illustrated in Drawings A and B where Deltat = period of pulse wave RDeltat = time of current pulse; 1 >/- R >/- 0.

In steady state J, (average atomic flux) = 0, where J is composed of a flux due to an electromigration force and a flux due to a solute concentration gradient force.

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For Eq. (2), Table I shows the concentration minimum as a function of stripe length and solubility for the condi...