Abstract
The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation may be difficult and time-consuming, and depending on the operator may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB processing, and the need to characterize specific devices requires a pre-FIB preparation method to isolate specific regions on the wafer. An innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent thinning by FIB has been developed. Based on controlled microcleaving technology, the system automatically performs the pre-FIB preparation in less than 30 minutes. An important added benefit is that the target area to be analyzed can be positioned at a specific distance from the sample edge, thereby facilitating the final FIB milling stage. The thinned specimen is automatically packaged for subsequent FIB processing and TEM. Details of the method and examples showing TEM results from tungsten filled vias are presented.
