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25 August 1997 Environmental and substrate material factors' effect on metal lithography corrosion
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Monitoring techniques were used to analyze metal lithography corrosion on post-metal etch processes and after solvent processing. Liquid ion chromatography (LIC) techniques were used to monitor the chlorine ion concentration on the wafers following plasma metal etch processing, and energy dispersive x-ray spectroscopy (EDS) techniques were used to monitor the level of fluorine ions which prevented native oxide growth that protects the metallization from solvent damage. Characterizations were run to identify the significant integrated circuit process factors and environmental conditions that increased the corrosion occurrence or severity above the baseline level. Monitoring of the environmental corrosion risk was done with LIC and air quality monitors. Wafer processing and substrate factors significant to corrosion occurrence were: (1) underlying oxide type, (2) photoresist type, (3) pattern density of the metal geometries, (4) metal etch wafer position, (5) connection to substrate by vias/contacts, (6) humidity, (7) backside condition of the wafer, (8) overetch step chlorine flow, and (9) metal thickness, in increasing significance. Significant reduction in measured corrosive ion levels and observed corrosion defects was obtained with modified processing schemes.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Karl E. Mautz "Environmental and substrate material factors' effect on metal lithography corrosion", Proc. SPIE 3213, Process, Equipment, and Materials Control in Integrated Circuit Manufacturing III, (25 August 1997);

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