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Reactive Etching of Silicon Nitride

IP.com Disclosure Number: IPCOM000088029D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Rozich, WR: AUTHOR

Abstract

This process allows the reactive ion etching of silicon nitride from a batch of around fifty wafers or less just prior to the silicon etching step in the formation of recessed oxide isolation. It also eliminates the need for the pyrolytic oxide deposition over the silicon nitride prior to its etching as well as the need to protect the backside of the wafer during the etching operation. The etch time for silicon nitride and the resist stripping times are significantly reduced.

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Reactive Etching of Silicon Nitride

This process allows the reactive ion etching of silicon nitride from a batch of around fifty wafers or less just prior to the silicon etching step in the formation of recessed oxide isolation. It also eliminates the need for the pyrolytic oxide deposition over the silicon nitride prior to its etching as well as the need to protect the backside of the wafer during the etching operation. The etch time for silicon nitride and the resist stripping times are significantly reduced.

The preferred etching process is for 2 1/4'' wafers using a LFE Corp. 1002 type plasma system: 1. Apply, expose and develop an etch resistant polymer, such as a thin coat, around one micron, of AZ 111*. 2. Perform a flash stripping operation for around 3 minutes at around 500 watts, 350 cc/min O(2) at 7 torr. 3. Etch the silicon nitride at low wattage in a mixture of CF(4) + O(2) gas at 200 cc/min at 3 torr. The etching time is a function of nitride thickness. 4. Strip the resist in O(2). * Trademark of Shipley Corp.

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