Two-step cyclic etching of copper thin ?lms was carried out using acetylacetone/O_2 gases and Ar plasma. The copper ?lm surfaces were ?rst modi?ed by exposing them to acetylacetone/O_2 gases and the modi?ed layers were removed via Ar-ion sputtering. The surface modi?cation step was optimized by varying the ?ow rate of the acetylacetone/O_2 gases and exposure time. The removal step was optimized by varying the dc-bias voltage to the substrate as well as sputtering time. The surface modi?cation and removal of the modi?ed layers were con?rmed by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The etch per cycle was estimated to be in the range of 0.7-3.0 nm. The cyclic etching of the copper ?lms using acetylacetone/O_2 gases and Ar sputtering revealed good etch pro?les with an etch slope of 70° without redepositions. It is proposed that the cyclic etching using acetylacetone/O_2 gases and Ar can be a suitable method to delineate the ?ne patterns on copper ?lms.
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