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Bevel cleaning using laser or ion beam

IP.com Disclosure Number: IPCOM000033548D
Original Publication Date: 2004-Dec-16
Included in the Prior Art Database: 2004-Dec-16
Document File: 1 page(s) / 23K

Publishing Venue

IBM

Abstract

Disclosed is a method for localized cleaning of the bevel and edge bead of silicon wafers by laser processing or ion beam processing. These techniques can be used to remove films in the bevel/edge bead, without damaging films in the device region.

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Bevel cleaning using laser or ion beam

Introduction:

During processing of integrated circuits, defects from the edge of the silicon wafer (bevel and edge bead regions) can fall off during high temperature processing and land in the device region. These defects can block patterning or film deposition, resulting in reduced yield. The defects are generally due to films that are inadvertently deposited on the bevel during processing. These films build up during processing and often have poor adhesion. When the films peel off the bevel, defects are formed.

"Backside" Wet cleans (that also wrap around the bevel) are often used to remove films from the bevel/edge bead. However, these cleans are difficult to use in practice, because multilayer films stacks can be undercut (i.e. going from the top edge bead towards the bottom of the bevel). Also, it is sometimes desirable to leave backside films in place (to reduce charge damage or electrochemical corrosion). Unfortunately, the backside wet clean removes desirable backside insulators as well as the undesirable bevel films.

Therefore , a method is required to remove films and other defects from the bevel and edge bead regions.

Summary of Invention:

Disclosed is a method for localized cleaning of the bevel and edge bead of silicon wafers by laser processing or ion beam processing. These techniques can be used to remove films in the bevel/edge bead, without damaging films in the device region.

Embodiment 1, Laser clean: Bevel films are removed by laser ablation or by heating in a reactive gas (for exampl...