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Bilayer Electron Beam Evaporation Crucible

IP.com Disclosure Number: IPCOM000092314D
Original Publication Date: 1968-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Cook, HC: AUTHOR [+2]

Abstract

Controlled heat transfer is obtained in vacuum evaporation crucibles by using a layer of a high heat conductivity material, such as water-cooled copper, and a low heat conductivity ceramic. This enables a controlled surface topography in a melt to be obtained at high deposition rates. This produces a more uniform thickness of film 6 on substrate 8 by providing a more uniform vapor stream 9. The crucible comprises block 10 of copper having one or more depressions 12 in its surface. The inside of a depression 12 is coated with a ceramic layer 14 such as Al(2)O(3). Heat is provided to the melt 16 by electron beam 17 from electron gun 18. The amount of heat conducted by copper 10 away from melt 16 depends on the thickness of layer 14.

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Bilayer Electron Beam Evaporation Crucible

Controlled heat transfer is obtained in vacuum evaporation crucibles by using a layer of a high heat conductivity material, such as water-cooled copper, and a low heat conductivity ceramic. This enables a controlled surface topography in a melt to be obtained at high deposition rates. This produces a more uniform thickness of film 6 on substrate 8 by providing a more uniform vapor stream 9. The crucible comprises block 10 of copper having one or more depressions 12 in its surface. The inside of a depression 12 is coated with a ceramic layer 14 such as Al(2)O(3). Heat is provided to the melt 16 by electron beam 17 from electron gun 18. The amount of heat conducted by copper 10 away from melt 16 depends on the thickness of layer 14. If layer 14 is very thin, the superheated area 19 of melt 16 from which significant evaporation occurs is very small. If layer 14 is increased in thickness, the size of superheaded area 19 of melt 16 is increased. Nonevaporation area 20 of melt 16 is at a lower temperature than superheated area 19. Consequently, contamination of the melt from the crucible is reduced substantially. Control of thermal transfer in this manner achieves the combination of high evaporation rate, more uniform thickness distribution of film 6 on substrate 8, and extended life of layer 14.

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