The SiLK resins, composed of aromatic hydrocarbons, are a family of highly cross-linked thermoset polymers with isotropic dielectric properties. Patterning of SiLK for high aspect ratio copper interconnects has depended on reactive ion etching with oxygen/nitrogen gas mixtures. Reactive ion etching is therefore also accomplished with reducing plasmas such as nitrogen/hydrogen. An additional plasma cleaning step can be inserted after the reactive ion etching (RIE) step, so that any residual contamination is removed prior to imaging or final sputter coating. Automated sample preparation of microelectronic materials containing high and low-k dielectrics for FESEM is accomplished in this article by combining these techniques: plasma cleaning, ion beam etching, and reactive ion etching. A single RIE chemistry was effective in etching both dielectrics as well as delineating the other phases present.

Standard analytical practice in the semiconductor industry depends on fast, efficient and reliable sample preparation prior to FESEM. “In lens” imaging technology and orientation mapping (EBSD) demand sample surfaces free of physical damage and residual contamination. An integrated preparation tool has been developed that incorporates the functionality necessary for argon – oxygen plasma cleaning, ion beam etching (IBE), reactive ion beam etching (RIBE), reactive ion etching (RIE), and ion beam sputter coating (IBSC). Control, monitoring and sequential automation of the processes is accomplished through a novel combination of software and hardware. FESEM results for Al and Cu based microelectronic materials will be discussed, as well as EBSD results for bulk metals. Improvements in throughput and subsequent materials characterization will be demonstrated.