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A Unique Process to Alleviate a Recursive Slope Situation

IP.com Disclosure Number: IPCOM000041059D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Feeley, JD: AUTHOR [+2]

Abstract

A method is described for alleviating a recursive slope in a layer of insulating materials. When plasma deposited silicon nitride and other insulating materials used in semiconductor processing are deposited on a steep slope caused by the underlying topography, the etching of a pattern on the slope sometimes results in a recursive slope in relation to the deposition of overlaying material.

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A Unique Process to Alleviate a Recursive Slope Situation

A method is described for alleviating a recursive slope in a layer of insulating materials. When plasma deposited silicon nitride and other insulating materials used in semiconductor processing are deposited on a steep slope caused by the underlying topography, the etching of a pattern on the slope sometimes results in a recursive slope in relation to the deposition of overlaying material.

Referring to Fig. 1, semiconductor substrate 10 has silicon oxide layer 12 and aluminum layer 14 deposited and patterned. Silicon nitride layer 16 is subsequently deposited and patterned using a reactive ion etch process. This sometimes results in a recursive slope 18, which if left in that state can result in cracking of subsequently applied metal levels.

This recursive slope 18 can be alleviated by the deposition of another layer of silicon nitride 20 as shown by the dotted line 22 in Fig. 2. This second layer 20 should be as thick or thicker than the original silicon nitride layer 16. Silicon nitride layer 20 is then blanket etched using reactive ion etching. The region 24 denoted by the cross hatching below the recursive slope 18 will remain filled in after the etching cycle is completed, thereby alleviating the recursive slope and avoiding the metal cracking problem in subsequent operations.

Disclosed anonymously.

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