Browse Prior Art Database

Hardening Silicon Wafers by Ion Implantation

IP.com Disclosure Number: IPCOM000086021D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Hu, SM: AUTHOR

Abstract

Thermal processing of silicon wafers, e.g., in the fabrication of integrated circuits, often induces dislocations which are generated at loci determined by surface irregularities and wafer edge irregularities, and then propagate inward toward the center of the wafer. In this connection, attention is directed to the paper, "Dislocations In Thermally Stressed Silicon Wafers", Applied Physics Letters, Volume 22, pp. 261 - 264, 1973. The detrimental affects of such dislocations are well known and need no discussion here. The present method relates to prevention of the propagation of such dislocations.

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Hardening Silicon Wafers by Ion Implantation

Thermal processing of silicon wafers, e.g., in the fabrication of integrated circuits, often induces dislocations which are generated at loci determined by surface irregularities and wafer edge irregularities, and then propagate inward toward the center of the wafer. In this connection, attention is directed to the paper, "Dislocations In Thermally Stressed Silicon Wafers", Applied Physics Letters, Volume 22, pp. 261 - 264, 1973. The detrimental affects of such dislocations are well known and need no discussion here. The present method relates to prevention of the propagation of such dislocations.

It has been found that ion implantation may be utilized to harden silicon wafers, and thus prevent the propagation of such dislocations.

For desirable results, with reference to the figure, ions are implanted to form an angular ring 11 about two millimeters wide along the perimeter of the upper surface 10 of the wafer shown in section. A similar angular ring may be formed along the perimeter of the bottom surface 12 of the wafer, or, a blanket implantation 13, as shown, may be formed over the entire back surface of the wafer, particularly when this back surface is not utilized for any devices in the integrated circuit.

Good results may be achieved by the following implantations:

Boron, utilizing an ion energy greater than 50 KeV at a dosage of about 0.5 x 10/16/cm/-2/directly into the surface of the silicon wafer, or by impla...