Selective dry etch removal of Si and SiOxNy for advanced electron beam probing applications

Abstract

This paper presents a global die level sample preparation technique utilizing selective etch chemistry and laser interferometry to expose the entire die top-most metal layer surface for Ebeam electrical FI. A novel Ebeam based probing technique referred to as StaMPS is introduced alongside this prep technique to isolate logic structure failures observed through SEM image contrasts at different logic states. By landing SEM probe tips on exposed metal pads and controlling logic states via an applied bias, the varying states produce different contrast within SEM imaging highlighting structural failure locations. This global prep technique in combination with StaMPS Ebeam FI creates faster FI/FA turn-around time by delivering a globally delayered full die in under an hour and creating opportunity to locate several defect types within a single sample.