Browse Prior Art Database

Sputtering Rate Monitor System

IP.com Disclosure Number: IPCOM000052135D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Cistola, AB: AUTHOR

Abstract

The sputtering disposition rate of a sputtering system is monitored by the acoustic emission caused by the target particle impact on a quartz rod/piezoelectric transducer probe.

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Sputtering Rate Monitor System

The sputtering disposition rate of a sputtering system is monitored by the acoustic emission caused by the target particle impact on a quartz rod/piezoelectric transducer probe.

Acoustic probe 10 is a cylindrical rod of insulator material, e.g., quartz, and is inserted and mounted into RF sputtering chamber C. A particle shield S prevents excessive build-up of the deposition material M from target T on the circumference of the probe 10.

Particles P of sputtered material M impacting the end face 11 of probe 10 transfer ultrasonic energy to it. Probe 10, acting as an acoustic waveguide, transfers the ultrasonic energy out through a vacuum seal to a sensitive piezoelectric transducer 12. The resonant frequency of transducer 12 is compatible with the bandwidth of the noise or acoustic emission caused by impacting particles P. The output of transducer 12 is fed to a conventional signal processor 13.

When the electrical signal arrives at the amplitude discriminator 14, it is separated out into various components depending on the amplitude of each signal being sensed by the piezoelectric transducer 12. The discriminator 14 discriminates low amplitude acoustic emission due to particle P impact on the probe 10 from high amplitude acoustic emission resulting from possible stresses in the deposited film on the probe face 11. The discriminator 14 includes memory circuits which allow the quantity of acoustic emission to be accumulatively counted...