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Increasing the Apparent Wall Area of an R.F. Sputtering System

IP.com Disclosure Number: IPCOM000074647D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Pennebaker, WB: AUTHOR

Abstract

In a driven substrate RF (radio frequency) sputtering system, the resputtering voltage becomes approximately equal to the RF substrate drive voltage when the wall area is much larger than the target and substrate areas. This is due to the fact that the RF plasma voltage is small when the wall area is large, and thus does not contribute significantly to the resputtering.

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Increasing the Apparent Wall Area of an R.F. Sputtering System

In a driven substrate RF (radio frequency) sputtering system, the resputtering voltage becomes approximately equal to the RF substrate drive voltage when the wall area is much larger than the target and substrate areas. This is due to the fact that the RF plasma voltage is small when the wall area is large, and thus does not contribute significantly to the resputtering.

In a production system where the target area is large, in relation to the wall area of the vacuum chamber, the RF plasma voltage may be undesirably large. However, this plasma voltage may be reduced, without increasing the wall area, by providing an inner wall which substantially covers the true grounded chamber walls. The use of such a technique provides a simple and economic method of minimizing the RF plasma voltage, thus providing direct correlation between the RF substrate drive voltage and resputtering.

The inner wall, as proposed, substantially covers the true grounded chamber walls. The inner wall is connected to true RF ground through a small inductance, which is set to a value where series resonance occurs with the capacitive discharge sheath contacting the inner wall. At series resonance the impedance between plasma and ground is minimized, and consequently the RF plasma voltage is also minimized.

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