Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

The use of in-situ lift-out combined with focused ion beam milling has become a favorable choice as it offers several indispensable advantages compared to the conventional mechanical and ex-situ lift-out sample preparation techniques. This paper discusses the procedures of the multiple-post in-situ lift-out grids preparation using a dicing saw. In addition, a real case is described to show that the multiple-post in-situ lift-out grids have been successfully applied to failure analysis. The multiple-post in-situ lift-out grids provide more positions and flatter surfaces for TEM sample mounting. The flat surface greatly increases the mounting efficiency and success rate. For the real case application, a thick Al fluoride oxide layer and Al corrosion were found above the Al bond pads, which had NOSP problem, and their neighbor area, respectively.

This paper provides details of a novel method developed to cover a tiny epoxy layer as an intermediate buffer on the site-specific surface defect using a micro-bush on the tip of a glass needle in a plucking system without sample surface damage and localization problems. It describes the method and some real cases. The microstructures are investigated using an FEI Tecnai TF20 field emission gun transmission electron microscopy equipped with a high angle annular dark field detector, an energy dispersive X-ray spectroscopy, and Gatan image filter systems. The paper explains the micro-brushes and buffer layer preparation though figures and illustrations.