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Proceedings Paper

Accurate photoresist usage forecasting
Author(s): Laird MacDowell
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Paper Abstract

Accurate photoresist usage forecasting is essential for smooth operation of semiconductor fabs, with over stocking leading to waste due to shelf life expiration and under stocking potentially leading to running out of photoresist with uplift in product demand. Most photoresists have a short shelf life, typically six months, long lead times for delivery and usage can vary significantly depending upon semiconductor product demand. Fabs with a large number of product types with a subsequent high number of different photoresists can be challenging to project accurate usage. Calculating monthly photoresist consumption involves more than multiplying wafer coating volume by wafer passes. Other critical factors that need to be included in the calculation are the number of photo tracks loaded with a particular photoresist, the frequency of the periodic dispense to waste to keep the delivery lines from drying, the consistency of the coating volume wafer to wafer, percent rework required and the number of process monitors run on the track. All of these factors can be combined to accurately project photoresist usage and data will be presented from the IBM 200 mm fab located in Essex Junction, Vermont showing projected versus actual usage of both low and high volume photoresists and the usage calculation methodology.

Paper Details

Date Published:
PDF: 5 pages
Proc. SPIE 6519, Advances in Resist Materials and Processing Technology XXIV, 65193R; doi: 10.1117/12.711185
Show Author Affiliations
Laird MacDowell, IBM Corp. (United States)

Published in SPIE Proceedings Vol. 6519:
Advances in Resist Materials and Processing Technology XXIV
Qinghuang Lin, Editor(s)

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