A Novel Approach for Enhancing Critical FIB Imaging for Failure Analysis and Circuit Edit Applications

Abstract

Abstract As semiconductor device features continue to decrease in size from merely sub micron to below 100 nanometers it becomes necessary to mill smaller and higher aspect ratio FIB vias with reduced ion beam current. This significantly reduces the number of secondary electrons and ions available for endpoint detection and imaging. In addition FIB gas assisted etching introduces a gas delivery nozzle composed of conductive material. This component is grounded to prevent charge build up during ion beam imaging or milling. The proximity of the nozzle to the sample surface creates a shielding effect which reduces the secondary electron detection level as well [1]. The ability to enhance secondary electron imaging for end point detection is required for successful FIB circuit edit and failure analysis applications on advanced technologies. This paper reviews the results obtained using FIB Assist, an image and signal enhancement product for the FEI / Micrion platform, for critical FIB endpoint determination. Examples of FIB fabricated probe points with 30 x 30 nm FIB vias and circuit edit applications endpointing on metal 1 with high aspect ratio holes are presented.