Browse Prior Art Database

In Situ Monitor of Ion Beam Film Growth and Etching

IP.com Disclosure Number: IPCOM000045154D
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Brosious, PR: AUTHOR [+4]

Abstract

Positioning a quartz crystal film thickness monitor in the ion beam path, identically with wafers to be processed, permits a dynamic monitoring of film thickness on the wafers as the film is grown and etched.

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In Situ Monitor of Ion Beam Film Growth and Etching

Positioning a quartz crystal film thickness monitor in the ion beam path, identically with wafers to be processed, permits a dynamic monitoring of film thickness on the wafers as the film is grown and etched.

The growth of compound films on metals by reactive ion beams has potential applications, such as the formation of thin oxide tunnel barriers for Josephson devices. Extremely fine control of layer thickness is required so that a method of directly monitoring film growth is needed. Also, film growth is often preceded by an etching (cleaning) step which must, also, be monitored.

Quartz crystal film thickness monitors have submonolayer sensitivity. Unfortunately, it is not possible to have the wafer to be processed and the monitor crystal at the same location. Since ion beams are not perfectly uniform, the monitor crystal does not see the exact same process seen by the wafer. The use of generic (testing) factors to recount for the differences is inadequate since the process is very sensitive and the ion beam spatial profile is very dependent upon process conditions.

The monitor consists of:
1. a quartz crystal which is
2. coated with a film of the material to be processed (e.g.

etched and oxidized) and
3. integrated into a rotating substrate holder assembly in a

position equivalent to that of a wafer (Fig. 1.).

As the holder 1 rotates, the wafers 2 move in and out of the beam 3 in turn, as does the monitor crys...