Browse Prior Art Database

High Temperature Lift-Off Structure

IP.com Disclosure Number: IPCOM000042508D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Marmillion, NP: AUTHOR [+3]

Abstract

A lift-off process is disclosed which uses the plasma etching of a silicon nitride or a silicon oxynitride layer through a pattern defined by a photoresist layer, to generate a high temperature lift-off structure capable of withstanding further processing steps associated with the deposition of lift-off films at temperatures that can exceed 350ŒC. In Fig. 1 there is shown a substrate 10 on which a silicon nitride (SiNx) film 12 is deposited through plasma enhanced chemical vapor deposition (PECVD). In one example a film of 700 nm of PECVD silicon nitride was deposited on a silicon substrate at about 350ŒC. The PECVD silicon nitride layer may be oxidized to produce an oxynitride surface on the nitride layer. This will make any nitride mask formed to have edges that do not erode.

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High Temperature Lift-Off Structure

A lift-off process is disclosed which uses the plasma etching of a silicon nitride or a silicon oxynitride layer through a pattern defined by a photoresist layer, to generate a high temperature lift-off structure capable of withstanding further processing steps associated with the deposition of lift-off films at temperatures that can exceed 350OEC. In Fig. 1 there is shown a substrate 10 on which a silicon nitride (SiNx) film 12 is deposited through plasma enhanced chemical vapor deposition (PECVD). In one example a film of 700 nm of PECVD silicon nitride was deposited on a silicon substrate at about 350OEC. The PECVD silicon nitride layer may be oxidized to produce an oxynitride surface on the nitride layer. This will make any nitride mask formed to have edges that do not erode. The desired pattern is formed on film 12 using a photoresist mask 14, as shown in Fig. 2, and by plasma etching to produce the nitride lift-off structure shown in Fig.
3. The recursive lift-off profile is obtained by varying the nitride composition throughout its film thickness so that a varying etch rate is obtained via isotropic plasma etching. Varying the temperature during the deposition process has been found to be effective. Following the removal of the photoresist mask, the structure is as shown in Fig. 4. A lift-off compatible material 16 is deposited on the lift-off structure, as shown in Fig. 5, using a high temperature directional deposition...