Novel Circuit Edit Solution for Bulk Copper Milling

Focused Ion Beam (FIB) circuit edit (CE) has been playing a pivotal role in providing insight to ramp-up yield. Numerous IC fabrication processes inherently pose unique challenges to FIB circuit edit approaches. Copper (Cu) has been the material of choice for interconnects as technology features shrink to the 180 nm node and below. Thick copper planes are used for multiple reasons that are mentioned later. Milling through thick copper planes has been tremendously challenging and time consuming during FIB circuit edits. Proposed is a methodology to enhance the bulk Cu removal process at astounding etching rates while maintaining planarity.