Paper
5 April 2012 Apply low-temperature plasma in the rework procedure of Al film structure to prevent pattern collapsed and CuAl2 precipitation
Jau Yu Tsai, Kung Hsun Tsao, Tsz Yuan Chen, Chih Chung Huang, Huan Hsin Yeh, Yu Huan Liu
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Abstract
In a conventional lithography process with Al film structure, the photo resist pattern is removed by two methods: wet etch or wet etch combine with dry strip process. There were some problems in these kinds of processes. Pattern collapsed after wet etch process due to the photo resist (PR) adhesion capability reduced. Contact angle can be the index to measure the adhesion capability. So as to prevent the pattern collapsed issue, a high-temperature plasma treatment step was added after wet etch. But it induces another issue. IC devices fabrication in Al interconnect process, 0.5wt% Cu is generally used in Al film deposition for better Al electron migration performance. The high-temperature Plasma with high potentiality of CuAl2 precipitation, which will form a residue cause the metal line bridge induce yield loss. In this paper, we modify the rework procedure and lower the plasma processing temperature to the "room temperature" to prevent the pattern collapsed issue and the CuAl2 precipitation. The modified rework procedure is not only improved the defect, WAT and yield, but also reduce the cycle time of resist remove process.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jau Yu Tsai, Kung Hsun Tsao, Tsz Yuan Chen, Chih Chung Huang, Huan Hsin Yeh, and Yu Huan Liu "Apply low-temperature plasma in the rework procedure of Al film structure to prevent pattern collapsed and CuAl2 precipitation", Proc. SPIE 8324, Metrology, Inspection, and Process Control for Microlithography XXVI, 83243B (5 April 2012); https://doi.org/10.1117/12.917888
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KEYWORDS
Plasma

Aluminum

Etching

Photoresist processing

Semiconducting wafers

Bridges

Wet etching

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