Browse Prior Art Database

Removal of Rie Induced Si(3)N(4) Ribbons

IP.com Disclosure Number: IPCOM000048962D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Marinaccio, FA: AUTHOR [+3]

Abstract

Anisotropic etching (reactive ion etching) used in achieving better resolution and tolerances of photoresist geometry does not etch an RIE induced coating from the sidewalls of a particular topology. The combination of anisotropic and isotropic etching resolves this problem without impact on resolution and tolerances.

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Removal of Rie Induced Si(3)N(4) Ribbons

Anisotropic etching (reactive ion etching) used in achieving better resolution and tolerances of photoresist geometry does not etch an RIE induced coating from the sidewalls of a particular topology. The combination of anisotropic and isotropic etching resolves this problem without impact on resolution and tolerances.

In the quest for smaller geometries and reduced dimensional tolerance, the etching process of semiconductor fabrication has become a mixture of plasma, conventional wet and reactive ion etching (RIE). Silicon nitride ribbons are generated by the interaction of anisotropic RIE and isotropic etching (plasma or wet). The formation of these ribbons is a function of shape overlap (product design) and layer to layer interaction (overlay/alignment). A schematic representation of ribbon formation is contained in Figs. 1, 2 and 3.

Yield reduction from these ribbons will result if they fall over an active area prior to a deposition or diffusion. Further yield loss could be anticipated from damage to subsequent layers as a result of the ribbon height. Normal cleaning methods, such as hot acid, mechanical and ultrasonic, were ineffective in removing these ribbons.

Since the ribbons are generated by edge effects of the masking overlaps, an isotropic Si(3)N(4) etch is required. The following process scheme is proposed to eliminate the ribbon formation: 1. Pattern formation in photoresist using typical

techniques.

2. Anisot...