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Tailored Grain Growth in Patterned Aluminum by Scanned Short Time Annealing

IP.com Disclosure Number: IPCOM000042136D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Iyer, SS: AUTHOR [+2]

Abstract

This article relates generally to the fabrication of interconnections in integrated circuits and more particularly to the formation of chains of single crystals in aluminum lines by scanning a heat source along the line. Aluminum-based metallization is fairly standard in the semiconductor industry today. The aluminum is usually evaporated onto the silicon wafer on pre-existing patterns through resist masks or is later patterned. In most cases, the material is polycrystalline with grain boundaries occurring randomly. Grain boundaries themselves have several undesirable features. They act as scattering centers and degrade electronic properties. They are also very susceptible to impurity precipitation and behave as corrosion centers.

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Tailored Grain Growth in Patterned Aluminum by Scanned Short Time Annealing

This article relates generally to the fabrication of interconnections in integrated circuits and more particularly to the formation of chains of single crystals in aluminum lines by scanning a heat source along the line. Aluminum-based metallization is fairly standard in the semiconductor industry today. The aluminum is usually evaporated onto the silicon wafer on pre-existing patterns through resist masks or is later patterned. In most cases, the material is polycrystalline with grain boundaries occurring randomly. Grain boundaries themselves have several undesirable features. They act as scattering centers and degrade electronic properties. They are also very susceptible to impurity precipitation and behave as corrosion centers. In addition, grain boundary transport phenomena, such as electromigration, are enhanced especially when grain boundaries run along current flow directions. It is therefore important from both performance and reliability standpoints to reduce the number of grain boundaries and also make them perpendicular to the direction of current flow. This is achieved by causing increased grain growth in a defined direction using a scanned filamentary heat source. A wafer with an aluminum pattern is placed on a heater plate (made of graphite, for example) and held at a moderate temperature (about 300OEC), while a long filamentary heat source (a graphite strip at N 600OEC) arr...