Browse Prior Art Database

Lift Off Method of Fabricating Thin Films

IP.com Disclosure Number: IPCOM000081580D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Weaver, LR: AUTHOR

Abstract

This method is useful in forming thin film patterns. It is especially useful in depositing patterns with good adhesion by vacuum deposition onto a heated substrate. While heated substrates are known to provide improved adhesion for vacuum deposited material, they are also known to cause polymerization and cross-linking in photoresist masks. These changes in the photoresist masks due to heating can make it difficult to lift off the mask after vacuum deposition. This difficulty is avoided by using a positive photoresist and, after aperture pattern formation, fully exposing the remaining photoresist before heating the substrate and vacuum depositing the thin film.

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Lift Off Method of Fabricating Thin Films

This method is useful in forming thin film patterns. It is especially useful in depositing patterns with good adhesion by vacuum deposition onto a heated substrate. While heated substrates are known to provide improved adhesion for vacuum deposited material, they are also known to cause polymerization and cross-linking in photoresist masks. These changes in the photoresist masks due to heating can make it difficult to lift off the mask after vacuum deposition. This difficulty is avoided by using a positive photoresist and, after aperture pattern formation, fully exposing the remaining photoresist before heating the substrate and vacuum depositing the thin film.

Referring to the figures, a layer of positive photoresist 10 is coated on substrate 11 using any desired coating and drying technique. A mask 12 having apertures or transparent portions 13 corresponding to a selected pattern is positioned over the positive photoresist 10, and the photoresist is exposed to actinic radiation in the selected pattern 14. Developer for the photoresist 10 is used to remove exposed pattern 14 from substrate 11, leaving aperture pattern 15 in the photoresist.

The remaining positive photoresist 10 is then completely exposed to actinic radiation. Subsequently, the substrate 11 is heated and thin film 16 is vacuum deposited. Then the remaining previously exposed positive photoresist 10 is removed using a developer. In the course of removing t...