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Novel Method to Achieve Negative Process Bias in a Contact or Via Hole

IP.com Disclosure Number: IPCOM000032497D
Original Publication Date: 2004-Nov-08
Included in the Prior Art Database: 2004-Nov-08
Document File: 2 page(s) / 35K

Publishing Venue

Motorola

Related People

Mark D. Hall: AUTHOR

Abstract

This disclosure describes a method in semiconductor manufacturing of producing a negative process bias at the top and bottom of a contact or via hole in order to extend photo and etch (i.e., patterning) tool capability. The novel integration relaxes the requirements on both photo and etch and enables the lifetime of both tool sets to be extended. Also, by having a negative process bias at the top and bottom of the contact hole, the risk of metal-to-contact (or via) hole shorts due to misalignment is greatly reduced. For brevity, only contact hole formation will be described herein.

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Novel Method to Achieve Negative Process Bias in a Contact or Via Hole

Mark D. Hall

This disclosure describes a method in semiconductor manufacturing of producing

a negative process bias at the top and bottom of a contact or via hole in order to extend photo and etch (i.e., patterning) tool capability.  The novel integration relaxes the requirements on both photo and etch and enables the lifetime of both tool sets to be extended.  Also, by having a negative process bias at the top and bottom of the contact hole, the risk of metal-to-contact (or via) hole shorts due to misalignment is greatly reduced.  For brevity, only contact hole formation will be described herein.

In current state-of-the-art semiconductor processes, single layer and bi-layer resist approaches are used to achieve a negative process bias for contact holes. These approaches relax the requirements on photo, but etch must clear a hole at minimum dimensions.  Also, the negative bias is achieved at the bottom of the contact hole while the top dimension remains large, leading to metal 1-to-contact leakage issues due to misalignment.

In the novel approach described herein, the contact hole is patterned at photo and etch using the largest dimensions possible that do not lead to bridging.  In the next step, a spacer is deposited in the contact hole and etched.  Next, the contact hole is filled with a resist or underlayer material to protect the spacer.  The resist or underlayer is then etched back using a dry...