Browse Prior Art Database

Skirt Removal Process for Metal Lift-Off

IP.com Disclosure Number: IPCOM000043884D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Dinklage, JB: AUTHOR [+2]

Abstract

This article describes a process that uses a non-selective ion etch to remove the skirt that often forms between the bottom of the fabricated line and the resist pedestal when using the customary image reversal metal lift-off process. This process also rounds the sharp metal corners of the top of the fabricated line. The process uses a non-selective ion etch to remove the skirt 11 after the metal lift-off step. The skirt material would probably etch more rapidly than a metal line or semiconductor surface because it is likely to be a spongy, porous material. This would enhance the ability to control the etch process. A general surface cleaning of the metal and semiconductor surface would result in improved adhesion of subsequent films.

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Skirt Removal Process for Metal Lift-Off

This article describes a process that uses a non-selective ion etch to remove the skirt that often forms between the bottom of the fabricated line and the resist pedestal when using the customary image reversal metal lift-off process. This process also rounds the sharp metal corners of the top of the fabricated line. The process uses a non-selective ion etch to remove the skirt 11 after the metal lift-off step. The skirt material would probably etch more rapidly than a metal line or semiconductor surface because it is likely to be a spongy, porous material. This would enhance the ability to control the etch process. A general surface cleaning of the metal and semiconductor surface would result in improved adhesion of subsequent films. Another problem in covering metal lines with subsequent chemical vapor deposition (CVD) passivation layers 12 is that the relatively sharp top metal corner 13 (which is inherent with either lift-off or subetch processes) causes CVD layer 12 to bulge 14 over the corner 13, leading to the formation of an undesirable cusp 15 at the bottom (Fig. 1). The non-selective ion etch rounds the metal corners 16 because sputter etching yields are greatest from a surface 3 45 degrees to the ion beam (Fig. 2). Thus, the disclosed process eliminates both the skirt and the sharp metal corners associated with metal lift-off. The reduction in metal cross-sectional area due to this process is insignificant and w...