Browse Prior Art Database

Negative Bias Masking Using Laser Endpoint Developing

IP.com Disclosure Number: IPCOM000037549D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Katz, SM: AUTHOR

Abstract

A difficulty encountered in optical lithography is the ability to repeatably reproduce images of varying sizes to zero print bias. A different print bias is typically seen between images of large and small size as well as for images in isolated versus evenly spaced pitches. A technique is disclosed herein which can minimize the bias variation seen in typical lithographic processing.

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Negative Bias Masking Using Laser Endpoint Developing

A difficulty encountered in optical lithography is the ability to repeatably reproduce images of varying sizes to zero print bias. A different print bias is typically seen between images of large and small size as well as for images in isolated versus evenly spaced pitches. A technique is disclosed herein which can minimize the bias variation seen in typical lithographic processing.

This technique consists of integrating laser endpoint develop with mask or reticle biasing and overdevelopment using a high contrast resist system. By overdeveloping the resist, all resist which has been even minimally exposed is developed away to the point where there is no dissolution in the exposed area which is greater than the dissolution rate of the unexposed area. At this point, lateral image size change in the resist is small creating a large process latitude. The image will be negatively biased so the resist lines will be smaller than the opaque areas used to create them. By using this bias in the design phase, the desired image size can be obtained through mask biasing.

The advantages of this system are:

1) more consistent bias control;

2) improved process latitude;

3) enhanced resist sidewall angles (>85 degrees); and

4) improved image contrast for submicron imaging.

Disclosed anonymously.

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