23 April 2001 Control and reduction of post-metal etch corrosion effects due to airborne molecular contamination
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Ionic contamination in microelectronic circuitry can have a detrimental effect on device reliability and yield. Post- aluminum etch corrosion has been considered a critical issue in dry plasma etching of aluminum. In this work, we review the actions taken to reduce the amount of defects due to Cl- induced corrosion in the metal lines at our manufacturing line in Lucent Technologies Madrid. Two approaches were followed in a parallel way: on one side manufacturing procedures were modified to reduce at the minimum the exposure of the unprotected metal lines to the clean room environment thus it is avoided any metal corrosion caused by a possible environmental contamination. The second working line was to improve the resistance to corrosion of the post-etched metal. With this aim, our efforts were focused on the passivation step just after the metal etch and prior the photoresist strip. The influence of several parameter settings of the passivation plasma on the resistance of the etched metal to corrosion has been studied. Accelerated corrosion tests were used to monitor the intrinsic metallization susceptibility of corrosion and chlorine and fluorine residuals content in the wafer were measured using ion-chromatography. It was found that a modification in the pressure, plasma power or duration of the passivation step could have a beneficial impact on the amount of chlorine residues left on the metal lines after etch and consequently an enhancement of their resistance to corrosion.
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Carmen Morilla, Carmen Morilla, Pilar Prieto, Pilar Prieto, Francisco Barbado, Francisco Barbado, } "Control and reduction of post-metal etch corrosion effects due to airborne molecular contamination", Proc. SPIE 4406, In-Line Characterization, Yield, Reliability, and Failure Analysis in Microelectronic Manufacturing II, (23 April 2001); doi: 10.1117/12.425266; https://doi.org/10.1117/12.425266

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