Browse Prior Art Database

Dual-Masking Metal Lift-Off Structures

IP.com Disclosure Number: IPCOM000060925D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Barber, JR: AUTHOR

Abstract

Current lift-off strategies employ the use of a single mask to expose a multiple-layered resist or an image reversible film. Both schemes suffer from lack of process stability, overall process complexity, and inordinate process length. The use of a dual-masking lift-off structure, as disclosed below, eliminates the exacting etch control necessary for multilayer resist and the depth of field concerns of single level image reversing processes. Referring to Fig. 1, a positive resist film 10 is applied on a substrate 12 using standard resist application techniques. The resist film 10 is then exposed through mask 14 which has been positively compensated; the spaces on the mask are larger then the desired line widths. At this point, unlike conventional resist patterning, the resist film 10 is not developed.

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Dual-Masking Metal Lift-Off Structures

Current lift-off strategies employ the use of a single mask to expose a multiple- layered resist or an image reversible film. Both schemes suffer from lack of process stability, overall process complexity, and inordinate process length. The use of a dual-masking lift-off structure, as disclosed below, eliminates the exacting etch control necessary for multilayer resist and the depth of field concerns of single level image reversing processes. Referring to Fig. 1, a positive resist film 10 is applied on a substrate 12 using standard resist application techniques. The resist film 10 is then exposed through mask 14 which has been positively compensated; the spaces on the mask are larger then the desired line widths. At this point, unlike conventional resist patterning, the resist film 10 is not developed. A second layer of resist 16 is then applied on top of resist film 10 (Fig. 2). Resist film 16 is then exposed through a second mask 18 with dimensions smaller than mask 14 (Fig. 3). Finally, the composite resist film is developed leaving a tiered lift-off structure, as seen in Fig. 4. Metal 20 can than be deposited and lifted off, as currently known in the art. The final metal structure after deposition is illustrated in Fig. 5.

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