Total measurement uncertainty and total process precision evaluation of a structural metrology approach to monitoring post-CMP processes

摘要

A new focused ion beam and electron beam based approach to metrology is used for accelerated process development of Chemical Mechanical Planarization (CMP) related back end processes. The technology is studied with the intention of employing it in rapid process development and high volume manufacturing. A structural metrology approach will include monitoring several features including low-k dielectric and Cu thickness as a function of pattern density. The study here will focus primarily on the film thickness of post-CMP low-k dielectric. The unique capabilities of the tool to cut, image and measure in a fully automated fashion, makes it necessary for us to evaluate the total process of sample preparation and measurement involved in this approach to metrology. We are therefore introducing the concept of total process precision to supplement a total measurement uncertainty analysis. In this paper we will report upon the analysis of work done to quantify this approach. This will involve a quantitative comparison of the tool metrology with a cross -sectional analysis SEM which is the most common best practice today.