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Browse Prior Art Database

RIE Planarization Process

IP.com Disclosure Number: IPCOM000039589D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 194K

Publishing Venue

IBM

Related People

Marinaccio, FA: AUTHOR [+3]

Abstract

This article concerns the development of an RIE (reactive ion etch) technique for planarizing semiconductor device wafers in order to alleviate adverse yield and reliability problems associated with non-planar surfaces. ROI (recessed oxide isolation) structures are often used to isolate semiconductor device structures. A raised, non-planar region commonly referred to as the 'bird's head', is a source of yield and reliability concerns. This non-planar region is often a stressed region in overlaying films, such as oxide, nitride, polysilicon and metal layers, its defects contributing to shorts and leakage paths in underlaying doped polysilicon structures where metal rails overlay the 'bird's head'.

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RIE Planarization Process

This article concerns the development of an RIE (reactive ion etch) technique for planarizing semiconductor device wafers in order to alleviate adverse yield and reliability problems associated with non-planar surfaces. ROI (recessed oxide isolation) structures are often used to isolate semiconductor device structures. A raised, non-planar region commonly referred to as the 'bird's head', is a source of yield and reliability concerns. This non-planar region is often a stressed region in overlaying films, such as oxide, nitride, polysilicon and metal layers, its defects contributing to shorts and leakage paths in underlaying doped polysilicon structures where metal rails overlay the 'bird's head'. Defects in the ROI head may also be caused by the RIE process, where the protective resist layer is expected to be thinner over the raised region. While the resist layer may be made thicker to alleviate this problem, the image definition will be sacrificed. These and other problems attributed to ROI structures may also be applicable to other isolation techniques, such as polysilicon trench structures, particularly if non-planar surfaces are created.

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This technique eliminates the above problems by application to the wafer (following formation of the ROI structure) of a planarizing film, such as a polyimide, or a photoresist material with etch rate properties similar to the material to be planarized. This coating should be of a thi...