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Proceedings Paper

CD uniformity improvement through elimination of hardware influences on post-exposure bake
Author(s): Jong Hoon Lim; Sung Ha Woo; Eui-Sang Park; Sang Pyo Kim; Dong Gyu Yim; Osamu Katada; Tobias Wähler; Peter Dress; Uwe Dietze
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Paper Abstract

The acceptable tolerance level for CD signatures induced by any process step in the mask manufacturing process has been dramatically reduced with each technology node. Chemical amplified resists (CAR) are used extensively for first layer mask imaging. Therefor a post exposure bake (PEB) process is required after resist exposure, adding yet another potential source of CD signatures. Consequentially, the thermal imprint of the bake process must be further reduced to meet the requirements of future technology nodes.

The influence of the measurement devices (wireless and wired sensor arrays) used to optimize the hotplate, on the performance of the Post Exposure Bake (PEB) process is discussed in [1,2]. A concept of utilizing two wired sensor arrays, with wire connections attached in opposite locations on the sensor array surface, called “Mirror Bake” is introduced. Based on the individual hotplate optimization for each of those two sensor arrays, a combined bake recipe for the multi-zone hotplate is calculated. This method eliminates the systematic temperature non-uniformity introduced by the sensor array hardware, when optimizing the recipes with only one sensor array.

In this paper the “mirror bake” concept is validated by comparing the CD uniformity data of masks manufactured with a PEB process, optimized using a single standard sensor array vs. the “mirror bake” concept. The “mirror bake” concept achieved a CD uniformity improvement of up to 30% (CD range). During this work additional hardware influences from the sensor arrays were identified.

Paper Details

Date Published: 8 November 2012
PDF: 7 pages
Proc. SPIE 8522, Photomask Technology 2012, 85222L (8 November 2012); doi: 10.1117/12.979470
Show Author Affiliations
Jong Hoon Lim, SK Hynix Semiconductor Inc. (Korea, Republic of)
Sung Ha Woo, Hynix Semiconductor Inc. (Korea, Republic of)
Eui-Sang Park, Hynix Semiconductor Inc. (Korea, Republic of)
Sang Pyo Kim, SK Hynix Semiconductor Inc. (Korea, Republic of)
Dong Gyu Yim, Hynix Semiconductor Inc. (Korea, Republic of)
Osamu Katada, SUSS MicroTec K.K. (Japan)
Tobias Wähler, SUSS MicroTec Photomask Equipment GmbH & Co. KG (Germany)
Peter Dress, SUSS MicroTec Photomask Equipment GmbH & Co. KG (Germany)
Uwe Dietze, SUSS MicroTec Inc. (United States)

Published in SPIE Proceedings Vol. 8522:
Photomask Technology 2012
Frank E. Abboud; Thomas B. Faure, Editor(s)

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