By Topic

First‐wafer effect in remote plasma processing: The stripping of photoresist, silicon nitride, and polysilicon

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $31
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
Loewenstein, Lee M. ; Semiconductor Process and Device Center, Texas Instruments Incorporated, Dallas, Texas 75265 ; Stefani, Jerry A. ; Butler, Stephanie Watts

Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1116/1.587196 

We have identified a first‐wafer effect for photoresist ashing and silicon nitride‐polysilicon stripping in remote plasma reactors. The first‐wafer effect consists of the first wafer etching differently from the subsequent wafers in a lot. For photoresist ashing, the first wafer ashes faster than subsequent wafers. For silicon nitride and polysilicon stripping, first wafers show higher etch rates of silicon nitride and polysilicon, while silicon dioxide first wafers etch faster for the polysilicon strip process, and slower for the silicon nitride strip process. We have modeled the first‐wafer effect for photoresist ashing. We found an inverse relationship between the percentage change in the time to clear the photoresist from the wafer and the time delay between processing sequential wafers. We have included this first‐wafer effect in the on‐line statistical process control strategy for the photoresist asher in our laboratory. Examination of this first‐wafer effect suggests that it may be caused by the generation of species in the discharge in the first few seconds of operation that alter the reactivity of the chamber walls. While these species are quick to adsorb on the walls, they only desorb slowly. Pumping on the chamber in the absence of a microwave discharge returns the chamber to its original state.

Published in:

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures  (Volume:12 ,  Issue: 4 )