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RF Sputtering Yield Measurements

IP.com Disclosure Number: IPCOM000095062D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Maissel, LI: AUTHOR

Abstract

Thin films of insulators deposited by RF sputtering are receiving greater attention. Insulators are sputtered by, alternately, ion bombardment and then electron bombardment. Radio frequencies are required in order to have the applied voltage switch in a time that is relatively short compared to that for the positive ion to traverse the distance from the edge of the ion sheet to the surface of the insulator. However, difficulties are encountered in accurately determining sputtering yield under RF conditions. This is because the current density and the ion energy are not well-known. Such information is necessary if maximum utilization of the technique is to be achieved.

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RF Sputtering Yield Measurements

Thin films of insulators deposited by RF sputtering are receiving greater attention. Insulators are sputtered by, alternately, ion bombardment and then electron bombardment. Radio frequencies are required in order to have the applied voltage switch in a time that is relatively short compared to that for the positive ion to traverse the distance from the edge of the ion sheet to the surface of the insulator. However, difficulties are encountered in accurately determining sputtering yield under RF conditions. This is because the current density and the ion energy are not well-known. Such information is necessary if maximum utilization of the technique is to be achieved.

This procedure measures sputtering yield, the number of insulator atoms yielded per incident ion. An electrode 10 in drawing A includes insulator 6 coated with two different metal films 2 and 4 whose DC sputtering yield is known. The metal films are adjacent one another but not contiguous or overlapping. Electrode 10 is then subjected to RF sputtering and the amount of metal, that is, M1 and M2, and insulator Mi removed in time t is determined by conventional techniques.

The equivalent RF sputtering yield is found with use of the sputtering relationship defined by M = S(v) J t. In the equation, M is the metal deposited, S is the sputtering yield at a given voltage, J is current density, and t is time of sputtering.

Since M is known for the metal films and both films...