Browse Prior Art Database

SiO Barrier Layer for Lift Off Process

IP.com Disclosure Number: IPCOM000088860D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Logan, JS: AUTHOR [+3]

Abstract

The lift-off process involves depositing the lift-off layer 5, such as a polysulfone, onto the substrate 6 to be treated. SiO layer 7 is deposited by evaporation onto the lift-off layer 5. SiO is a transparent film, and therefore can be used for optical, as well as E-beam lithography. A photoresist layer 8 is deposited onto layer 7. The photoresist layer 8 is exposed and developed to form opening 9 by conventional techniques to result in the Fig. 1 structure.

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SiO Barrier Layer for Lift Off Process

The lift-off process involves depositing the lift-off layer 5, such as a polysulfone, onto the substrate 6 to be treated. SiO layer 7 is deposited by evaporation onto the lift-off layer 5. SiO is a transparent film, and therefore can be used for optical, as well as E-beam lithography. A photoresist layer 8 is deposited onto layer 7. The photoresist layer 8 is exposed and developed to form opening 9 by conventional techniques to result in the Fig. 1 structure.

The photoresist layer 8 is used as the mask for a reactive ion etch process to remove the exposed portions of layer 7. At this point, a large fraction of layer 8 has been removed. Layer 7 then acts as a mask during reactive ion etching of layer 5 in O(2). The substrate can now be processed, as desired, using the layers 5 and 7 as the mask. After the processing, the lift-off layer 5 is removed by a suitable solvent, which results in the break-up and removal of layer 7.

The SiO provides a conformal coating so that the film thickness will be the same everywhere on a wafer, including via holes. A thinner layer of SiO than organo silicone is necessary as a barrier layer, about 1000 Angstroms, so that the photoresist thickness on the top can be comparatively thin.

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