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Proceedings Paper

Investigation of UFO defect on DUV CAR and BARC process
Author(s): Siew Ing Yet; Bong Sang Ko; Soo Man Lee; Mike May
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Paper Abstract

Photo process defect reduction is one of the most important factors to improve the process stability and yield in sub-0.18um DUV process. In this paper, a new approach to minimize the Deep-UV (DUV) Chemically Amplified Resist (CAR) and Bottom Anti-Reflective Coating (BARC) induced defect known as UFO (UnidentiFied Object) defect will be introduced. These defects have mild surface topography difference on BARC; it only exists on the wide exposed area where there is no photoresist pattern. In this test, Nikon KrF Stepper & Scanner and TEL Clean track were used. Investigation was carried out on the defect formulation on both Acetal and ESCAP type of photoresist while elemental analysis was done by Atomic Force Microscope (AFM) & Auger Electron Spectroscopy (AES). Result indicated that both BARC and photoresist induce this UFO defect; total defect quantity is related with Post Exposure Bake (PEB) condition. Based on the elemental analysis and process-split test, we can conclude that this defect is caused by lack of acid amount and low diffusivity which is related to PAG (Photo Acid Generator) and TAG (Thermal Acid Generator) in KrF photoresist and BARC material. By optimizing photoresist bake condition, this UFO defect as well as other related defect such as Satellite defect could be eliminated.

Paper Details

Date Published: 24 May 2004
PDF: 9 pages
Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); doi: 10.1117/12.535034
Show Author Affiliations
Siew Ing Yet, 1st Silicon Pte., Ltd. (Malaysia)
Bong Sang Ko, 1st Silicon Pte., Ltd. (Malaysia)
Soo Man Lee, 1st Silicon Pte., Ltd. (Malaysia)
Mike May, 1st Silicon Pte., Ltd. (Malaysia)


Published in SPIE Proceedings Vol. 5375:
Metrology, Inspection, and Process Control for Microlithography XVIII
Richard M. Silver, Editor(s)

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