Experimental study of NiFe and CoFe throughmask electrodeposition of high aspect ratio features

Abstract

The electrodeposition of NiFe and CoFe onto rotating disk electrodes and into high aspect ratio features in 300 μm-thick photoresist was studied using electrolytes previously considered in the literature. The through-thickness uniformity of the plated features was characterized with reference to the rotating disk electrode results. Current efficiencies for various deposition conditions were also characterized. The composition of NiFe was more sensitive to mixing than CoFe on a rotating disk electrode. This sensitivity was reflected in the higher nonuniformity in general of the plated high aspect ratio NiFe features; a feature with an aspect ratio of three showed decreasing Fe content towards the feature bottom, with the Fe content at the bottom less than half that at the top. CoFe showed only slightly decreasing Fe content for the same aspect ratios. The composition of both alloys near the feature opening (where more mixing occurs) was consistent with that of deposits obtained from rotating disk electrodes at high rotation rates.