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Laser-Addressable Metal Connections

IP.com Disclosure Number: IPCOM000042468D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kinney, WI: AUTHOR [+2]

Abstract

A method is provided for selectively producing electrical connections in semiconductor devices after metallization is completed. Connections can be made at specially prepared sites either within one level or between different levels of metal to implement circuit design iterations or to select among redundant connections following the electrical test of the devices. This is accomplished by providing conductive lines to be isolated using intrinsic amorphous silicon at certain preselected locations, where an electrical connection may be needed. When an electrical connection between the lines is needed, pulsed energy from a laser is directed towards the amorphous silicon between the conductive lines causing the silicon to melt and interdiffuse with the metal (i.e.

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Laser-Addressable Metal Connections

A method is provided for selectively producing electrical connections in semiconductor devices after metallization is completed. Connections can be made at specially prepared sites either within one level or between different levels of metal to implement circuit design iterations or to select among redundant connections following the electrical test of the devices. This is accomplished by providing conductive lines to be isolated using intrinsic amorphous silicon at certain preselected locations, where an electrical connection may be needed. When an electrical connection between the lines is needed, pulsed energy from a laser is directed towards the amorphous silicon between the conductive lines causing the silicon to melt and interdiffuse with the metal (i.e., aluminum) of the conductive lines to form an electrical connection. A Q-switched frequency doubled Nd:YAG laser has been used to melt the amorphous silicon between two aluminum lines. A precise aiming of the laser is not required because the power required to melt the silicon has little effect on the aluminum. This is due to aluminum's higher reflectivity and its higher thermal diffusivity. This self-aligned feature of the process may be enhanced, in the application of making corrections between two levels of metal, by providing an opening in the interior of the upper metal line, which does not break the electrical continuity of this line, but exposes the underlying amor...