Browse Prior Art Database

Evaporation Mask

IP.com Disclosure Number: IPCOM000086940D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 19K

Publishing Venue

IBM

Related People

Mansbridge, DS: AUTHOR [+2]

Abstract

Thin-film transistors are made by sequential evaporations through metal masks. The source/drain gap should be as small as possible and is usually defined by laying fine wires across etched holes in the metal sheet. Where, as is usually the case, many devices are formed with the same mask, the alignment of the wires is difficult. Direct etching of a metal mask does not give satisfactory results.

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Evaporation Mask

Thin-film transistors are made by sequential evaporations through metal masks. The source/drain gap should be as small as possible and is usually defined by laying fine wires across etched holes in the metal sheet. Where, as is usually the case, many devices are formed with the same mask, the alignment of the wires is difficult. Direct etching of a metal mask does not give satisfactory results.

The problems are avoided by applying photoresist 1 on a metal sheet 2 (Fig.
1), forming the required mask pattern on the photoresist, and etching the metal sheet from both sides to give the cross section of Fig. 2. The photoresist is then protected and passivated by electroless deposition of about one micron of metal. The passivated photoresist forms the required mask, and material is deposited from the direction of the arrow in Fig. 2.

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