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Monitoring Process Induced Contaminations in Si Wafers

IP.com Disclosure Number: IPCOM000085841D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR

Abstract

Rapidly diffusing contaminations are gettered on defects having a known density. Samples whose thickness has been reduced by etching are analyzed under an electron microscope by energy dispersive X-ray analysis. This permits process induced contaminations to be determined semiquantatively down to 10/-15/ g per wafer.

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Monitoring Process Induced Contaminations in Si Wafers

Rapidly diffusing contaminations are gettered on defects having a known density. Samples whose thickness has been reduced by etching are analyzed under an electron microscope by energy dispersive X-ray analysis. This permits process induced contaminations to be determined semiquantatively down to 10/- 15/ g per wafer.

In a surface layer of a monitor wafer additionally used during the actual semiconductor process several local dislocation sources are generated, for example, by ion implantation. The wafer is raised to a temperature at which the diffusion length of the contaminations to be analyzed is at least of the order of the crystal dimensions. From this temperature the wafer is cooled slowly, so that the contaminations are precipitated on the dislocation sources and the dislocations caused by them, respectively.

The actual analysis is carried out by the characteristic X-rays produced by the high-energy electrons. The X-rays are analyzed by an energy dispersive spectrometer. Analysis is carried out on a chemically thinned area, using an electron microscope. This permits an extremely sensitive semiquantative analysis of the various elements independent of their type.

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