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Multiple Hearth Evaporation Source used for Getter Pumping

IP.com Disclosure Number: IPCOM000088444D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Giddings, JJ: AUTHOR [+3]

Abstract

Getter pumps are trapping devices which employ reactive materials to bind residual gases on the inner surface of a vacuum system. The trapping agents are freshly prepared metal films which capture gases by several mechanisms, a phenomenon referred to as cleanup. Widely used getter materials are Ba, Ti, Mo and Ta. The most effective getter material is Ta, which takes up H(2) and CO twice as fast as the next best materials, Ti and Mo.

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Multiple Hearth Evaporation Source used for Getter Pumping

Getter pumps are trapping devices which employ reactive materials to bind residual gases on the inner surface of a vacuum system. The trapping agents are freshly prepared metal films which capture gases by several mechanisms, a phenomenon referred to as cleanup. Widely used getter materials are Ba, Ti, Mo and Ta. The most effective getter material is Ta, which takes up H(2) and CO twice as fast as the next best materials, Ti and Mo.

Although Ta is the most effective getter, it is rarely used because it requires very high evaporation temperatures. Ta could be used in an evaporation chamber where such temperatures are achievable. However, system geometric considerations frequently restrict the installation of a getter pump because of insufficient space as, for example, in the Temescal :FC 1800* evaporator.

For semiconductor metallurgy which requires a three metal in situ evaporation which is accomplished by incorporating a multiple hearth turret E- gun source in the :FC 1800 evaporator, an unused hearth can readily be adopted for gettering.

In the figure, which illustrates the turret source, hearths A, C and D may contain the metals to be evaporated and hearth B the getter material. In operation, assume the evaporation of one of the metals from hearth A causes the release of a contaminant, e.g., H(2). The evaporation of the getter material from hearth B on to a shutter in sequence removes the H(2).

Getterin...