Automated Sample Preparation of Packaged Microelectronics for FESEM

A packaged device based on a ball grid array or other design presents a challenge to the failure analyst. Accessing one of the metal levels from the topside requires decapsulation by either a wet, predominantly dry (RIE) or a completely dry (mechanical) treatment. To reveal the details of the gate including the gate oxide, new approaches to selective etch delineation by RIE are required. This article presents an automated sample preparation method for packaged microelectronic materials by combining plasma cleaning, ion beam etching, reactive ion etching and ion beam sputter coating. A single etch gas chemistry was effective in phase delineation by RIE. Future work to further delineate the gate oxides could support accurate metrology by means of FESEM rather than field emission transmission electron microscope.