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Etching Process for Silicon Nitride

IP.com Disclosure Number: IPCOM000080951D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Edel, WA: AUTHOR [+2]

Abstract

Silicon nitride is widely used in the semiconductor industry for dielectric and passivation purposes. A photolithography process combined with subtractive etching of the silicon nitride has problems. The etchant used to etch silicon nitride frequently has a deteriorating effect on the photoresist. An effort to alleviate these problems has been to use a silicon oxide mask on the surface of the silicon nitride, which can be fabricated by photolithographic processes, and subsequently used as a mask to etch silicon nitride.

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Etching Process for Silicon Nitride

Silicon nitride is widely used in the semiconductor industry for dielectric and passivation purposes. A photolithography process combined with subtractive etching of the silicon nitride has problems. The etchant used to etch silicon nitride frequently has a deteriorating effect on the photoresist. An effort to alleviate these problems has been to use a silicon oxide mask on the surface of the silicon nitride, which can be fabricated by photolithographic processes, and subsequently used as a mask to etch silicon nitride.

In this method, a layer of Si(3)N(4) is deposited on the substrate, and the surface of the silicon nitride oxidized. The oxidation can be accomplished with a cycle as simple as fifteen minutes at 1,000 Degrees C in oxygen. The resultant layer is then etched using standard photolithographic processes and subtractive etching. The resultant layer of oxidized silicon nitride is then used as an etchant mask, where the nitride can be etched in a refluxing phosphoric acid solution at 180 Degrees C.

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