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Via Hole Contact Resistance Yield Improvement

IP.com Disclosure Number: IPCOM000048593D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Shatzkes, M: AUTHOR [+2]

Abstract

It is difficult to prevent thin films of an insulating nature from forming on first level metal during the process steps preceding the deposition of a second level metal in the manufacture of semiconductor integrated circuits. It is possible to remove this film by, for example, sputter etching. However, sputtering has the disadvantage of affecting masking layers and line dimensions as well as the thin film.

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Via Hole Contact Resistance Yield Improvement

It is difficult to prevent thin films of an insulating nature from forming on first level metal during the process steps preceding the deposition of a second level metal in the manufacture of semiconductor integrated circuits. It is possible to remove this film by, for example, sputter etching. However, sputtering has the disadvantage of affecting masking layers and line dimensions as well as the thin film.

The thin insulating intervening layer between the first and second level metal can be disrupted in several ways to reduce contact resistance without resorting to sputter etching. Subsequent metal anneal will cause the metals to interdiffuse and form good contacts. Ion implantation with a large atom like xenon in high dosages and low energy prior to the second metal deposition can disrupt the thin film. The range of these atoms is in the order of the interfacial film thickness which is typically about 200 A. Alternatively, low energy ion implantation of a metal whose range (ion implant peak) is of the order of the thickness of the interfacial layer itself is useful in causing the film disruption. Aluminum is suitable for this purpose. Another alternative method achieves film disruption by mixing the interfacial material with metal or by evaporating the film and removing it. This can be accomplished by using a laser whose wavelength is chosen such that its energy is strongly absorbed at the first metal surface, but w...