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A MODIFIED RATE MONITOR

IP.com Disclosure Number: IPCOM000023793D
Original Publication Date: 1979-Feb-28
Included in the Prior Art Database: 2004-Mar-31
Document File: 2 page(s) / 260K

Publishing Venue

Xerox Disclosure Journal

Abstract

The rate of evaporation of metals in a vapor deposition process is controlled by monitoring vapor content of the evaporation chamber rather than the temperature of the evaporation crucible. In the figure, evaporation chamber 1 houses crucible 2 which is electrically heated from power supply 3. Power supply 3 is alternatively

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XEROX DISCLOSURE JOURNAL

A MODIFIED RATE MONITOR

Warren K. Bower Chong T. Wan

Proposed Classification

U.S. Cl. 219/272 Int. Cl. F22b

The rate of evaporation of metals in a vapor deposition process is controlled by monitoring vapor content of the evaporation chamber rather than the temperature of the evaporation crucible. In the figure, evaporation chamber 1 houses crucible 2 which is electrically heated from power supply 3. Power supply 3 is alternatively

controlled by a voltage produced by a Thermac controller 4 or by means of switch 5 directly from a voltage produced by continuous rate monitor 7 also driving a strip

chart recorder 6 through switch 5, The continuous rate monitor produces a voltage by means of sensing the vapor density through sensor 8,

6

Volume 4 Number 1 january/February 1979 33

[This page contains 1 picture or other non-text object]

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A MODIFIED RATE MONITOR (Cont~d)

A commercially available Sentinel sensor admits a beam of vapor which interacts with a stream of electrons. A portion of the generated optical signal is then

collected through optical window 9 and filter 10 by photodetector 11, In order to maximize the efficiency of the small optical signal from sensor 8, window 9 is heated to prevent a collection of condensate. The technique utilized by the

Sentinel optical sensor is electron impact emission spectroscopy, whereby atoms can be excited by collisions with electrons to emit a characteristic wavelength, thus detecting the va...