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Multilayer Metallurgy Incorporating a Reactive Ion Etch Stop for Aluminum on Polyimide

IP.com Disclosure Number: IPCOM000062678D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 19K

Publishing Venue

IBM

Related People

Bausmith, RC: AUTHOR [+2]

Abstract

Where it is desired to pattern aluminum or aluminum alloy films atop polyimide by reactive ion etching (RIE), an etch stop film comprised of a material which is not etched by a chlorinated or oxygenated etch plasma but can be etched in a fluorinated plasma is interposed between the aluminum and the polyimide. Referring to the figure, a thin layer of an etch stop material such as tungsten (W) is deposited on the polyimide 2. The aluminum- based film 4 is next deposited. Following photoresist deposition and patterning, the aluminum film 4 is etched in a chlorinated RIE process leaving the aluminum structures, e.g., 4, with photoresist 6 on top. Photoresist 6 is next removed by an oxygen plasma RIE process step.

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Multilayer Metallurgy Incorporating a Reactive Ion Etch Stop for Aluminum on Polyimide

Where it is desired to pattern aluminum or aluminum alloy films atop polyimide by reactive ion etching (RIE), an etch stop film comprised of a material which is not etched by a chlorinated or oxygenated etch plasma but can be etched in a fluorinated plasma is interposed between the aluminum and the polyimide. Referring to the figure, a thin layer of an etch stop material such as tungsten (W) is deposited on the polyimide 2. The aluminum- based film 4 is next deposited. Following photoresist deposition and patterning, the aluminum film 4 is etched in a chlorinated RIE process leaving the aluminum structures, e.g., 4, with photoresist 6 on top. Photoresist 6 is next removed by an oxygen plasma RIE process step. The tungsten film W is then selectively removed by a fluorinated plasma RIE process step, leaving the structure shown in the figure. The etch stop film W prevents both chlorine embedment in the polyimide 2 during aluminum etching and attack of the polyimide 2 during removal of photoresist. In addition, the W is not attacked by the chlorinated or oxygenated plasma RIE processes. The fluorinated plasma RIE process for removal of unprotected W does not attack the aluminum 4 nor does it leave an embedded residue in the polyimide which could lead to later corrosion of the aluminum.

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