Cross-sectioning is a necessary technique for the failure analysis of integrated circuits. Historically, the majority of samples have been prepared for scanning electron microscope (SEM) analysis. Today's smaller geometry devices, however, increasingly require the improved spatial resolution afforded by the transmission electron microscope (TEM), both in imaging analysis and in elemental analysis. Specific-area cross-section TEM (SAXTEM) analysis allows the failure analyst to identify defects that may go undiscovered in the SEM. A procedure is described for a timely preparation of SAXTEM samples using a focused ion beam (FIB) instrument and a manipulator probe. This procedure extends the state-of-the-art in several key respects: A) no mechanical grinding is necessary, B) samples as large as the FIB chamber can be accommodated, e.g., whole wafers, C) multiple samples can be prepared from one die, D) the procedure is faster and more repeatable than previously reported procedures.
Transmission Electron Microscopy (TEM) Sample Preparation (SP) has developed greatly in the recent years, mainly in the area of Focus Ion Beam (FIB). The FIB became the ultimate solution for site specific TEM SP, as the specimen can be imaged for exact placement of the final milling window (DualBeam™ instrument). While the FIB offers great advantages, re precision, ease of use and mostly independent from the nature of the sample material, it is costly (both on capital investment and cost of operation -COO), the thinned area is small (microns), surface amorphization is visible in semiconductor materials, and possibly form Ga intermetallic compounds.One of the preferred alternative method to FIB for non site specific SP and to overcome the FIB disadvantages is mechanical polishing of a wedge sample to transparency with final broad Ar ion beam milling. This method can process both plan view and cross section view specimens, producing large thin area and reduce broad ion milling times to minutes. This method is low on costs, offer a solution for large area investigation and for Ga sensitive material.The biggest drawback for this method is its absolute reliance on technician experience and expertise and of course, natural human limitations. The control over polishing parameters, such as time, angle, force is coarse. The ability to incrementally, on going fine-adjust the parameters, while transferring between polisher and microscope is limited. Therefore, the success and repeatability rate are hard to predict, while the process is long and cumbersome. This paper will describe a hands-free, automated wedge TEM SP technique, which offers all the advantages of mechanical polishing of a wedge sample, while eliminating the disadvantages described in the previous paragraph. The sample is processed by a computer control polishing system with an in situ microscope, CCD, advance image processing and 3D angle control. The system integrates the polishing, the imaging, the on going fine-adjustments of the polishing parameters and the closed loop end point steps hands-free. Consequently, successful results are obtained by any user after a short training cycle. Fine control over the polishing parameters allows increased precision, larger thinned area (1mm), high success rate and repeatability at high throughput. This technique can also be used to prepare a thin, <2-3um specimen for FIB, which will reduce FIB milling time and a reduced fluorescence yield contribution from the neighboring material in analytical TEM investigations with energy-dispersive x-ray analysis (EDX). Experiments are in progress to use this technique to prepare a thin specimen that is TEM ready and eliminate ion mill step all together, FIB or broad beam.
This paper is concerned with characterization and failure analysis challenges posed by 3D integration of semiconductor devices, with a particular focus on wafer bonded components and Through Silicon Vias (TSV). Requirements for sample preparation are discussed, along with advantages and limitations exhibited by various different techniques. Analysis examples with real devices are presented, along with successful sample preparation solutions enabled by a precision polishing toolset.
Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008
Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.