Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Lift Off Mask

IP.com Disclosure Number: IPCOM000081333D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR [+2]

Abstract

Effective lift-off masks for generating conductive patterns on substrate must have overhanging edges, which can be produced by using pyrolytic silicon oxides with a graded etch rate perpendicular to the mask surface as masking material.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Lift Off Mask

Effective lift-off masks for generating conductive patterns on substrate must have overhanging edges, which can be produced by using pyrolytic silicon oxides with a graded etch rate perpendicular to the mask surface as masking material.

To generate the mask, a layer of pyrolytic oxide 1 is grown on substrate 2. During the oxide growth, the temperature is continuously changed from, for example, 300 to 500 degrees C. This temperature variation results in a graded etch rate in the oxide layer 1, so that if the oxide layer is covered with a photoresist mask 3 (Fig. 1) corresponding to the desired pattern and then etched with buffered hydrofluoric acid, an etch profile (Fig. 2) with overhanging edges is generated. After stripping off the photoresist, the mask 3 is finished.

To produce the desired pattern, metal 4 is subsequently evaporated over the full surface, thus generating a structure, a cross-sectional view of which is shown in Fig. 3. Finally, the pyrolytic oxide 1 and the metal 4 covering it are removed.

1

Page 2 of 2

2

[This page contains 1 picture or other non-text object]