Low keV FIB Applications for Circuit Edit

Author(s):  
Chad Rue ◽  
Randall Shepherd ◽  
Roy Hallstein ◽  
Rick Livengood

Abstract Focused ion beam (FIB) tools are used to perform "circuit edit," (CE), in which existing integrated circuit devices are modified to create prototype devices that simulate potential mask changes. Although ion milling at low keV is common in TEM sample preparation, the technique has not become commonplace for CE applications. This is because most commercial FIB systems are optimized for either 30 or 50 keV. Recent work in the laboratories of FEI and Intel have attempted to apply low keV FIB processing to cutting small copper lines on advanced IC devices. The majority of this paper focuses on water-assisted, low keV copper etching. Secondary objectives of this work are to raise general awareness among FIB users of the potential benefits of low keV processing, to speculate on the physical mechanisms involved, and to discuss some of the technical difficulties associated with low keV FIB operation.

Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo

Abstract 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.


Author(s):  
Chin Kai Liu ◽  
Chi Jen. Chen ◽  
Jeh Yan.Chiou ◽  
David Su

Abstract Focused ion beam (FIB) has become a useful tool in the Integrated Circuit (IC) industry, It is playing an important role in Failure Analysis (FA), circuit repair and Transmission Electron Microscopy (TEM) specimen preparation. In particular, preparation of TEM samples using FIB has become popular within the last ten years [1]; the progress in this field is well documented. Given the usefulness of FIB, “Artifact” however is a very sensitive issue in TEM inspections. The ability to identify those artifacts in TEM analysis is an important as to understanding the significance of pictures In this paper, we will describe how to measure the damages introduced by FIB sample preparation and introduce a better way to prevent such kind of artifacts.


Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
R. Li ◽  
M.L. Ray ◽  
P.E. Fischione ◽  
...  

Abstract Fast and accurate examination from the bulk to the specific area of the defect in advanced semiconductor devices is critical in failure analysis. This work presents the use of Ar ion milling methods in combination with Ga focused ion beam (FIB) milling as a cutting-edge sample preparation technique from the bulk to specific areas by FIB lift-out without sample-preparation-induced artifacts. The result is an accurately delayered sample from which electron-transparent TEM specimens of less than 15 nm are obtained.


1997 ◽  
Vol 3 (S2) ◽  
pp. 357-358
Author(s):  
C. Amy Hunt

The demand for TEM analysis in semiconductor failure analysis is rising sharply due to the shrinking size of devices. A well-prepared sample is a necessity for getting meaningful results. In the past decades, a significant amount of effort has been invested in improving sample preparation techniques for TEM specimens, especially precision cross-sectioning techniques. The most common methods of preparation are mechanical dimpling & ion milling, focused ion beam milling (FIBXTEM), and wedge mechanical polishing. Each precision XTEM technique has important advantages and limitations that must be considered for each sample.The concept for both dimpling & ion milling and wedge specimen preparation techniques is similar. Both techniques utilize mechanical polishing to remove the majority of the unwanted material, followed by ion milling to assist in final polishing or cleaning. Dimpling & ion milling produces the highest quality samples and is a relatively easy technique to master.


2016 ◽  
Vol 850 ◽  
pp. 722-727 ◽  
Author(s):  
Hui Wang ◽  
Shang Gang Xiao ◽  
Qiang Xu ◽  
Tao Zhang ◽  
Henny Zandbergen

The preparation of thin lamellas by focused ion beam (FIB) for MEMS-based in situ TEM experiments is time consuming. Typically, the lamellas are of ~5μm*10μm and have a thickness less than 100nm. Here we demonstrate a fast lamellas’ preparation method using special fast cutting by FIB of samples prepared by conventional TEM sample preparation by argon ion milling or electrochemical polishing methods. This method has been applied successfully on various materials, such as ductile metallic alloy Ti68Ta27Al5, brittle ceramics K0.5Na0.5NbO3-6%LiNbO3 and semiconductor Si. The thickness of the lamellas depends on the original TEM sample.


1998 ◽  
Vol 4 (S2) ◽  
pp. 656-657 ◽  
Author(s):  
David W. Susnitzky ◽  
Kevin D. Johnson

The ongoing reduction of scale of semiconductor device structures places increasing demands on the sample preparation methods used for transmission electron microscopy (TEM). Much of the semiconductor industry's failure analysis and new process development effort requires specific transistor, metal or dielectric structures to be analyzed using TEM techniques. Focused ion beam (FIB) milling has emerged as a valuable technique for site-specific TEM sample preparation. FIB milling, typically with 25-50kV Ga+ ions, enables thin TEM samples to be prepared with submicron precision. However, Ga+ ion milling significantly modifies the surfaces of TEM samples by implantation and amorphization. Previous work using 90° milling angles has shown that Ga+ ion milling of Si produces a surface damage layer that is 280Å thick. This damage is problematical since the current generation of semiconductor devices requires TEM samples in the 500-1000Å thickness range.


Author(s):  
S. J. Kirch ◽  
Ron Anderson ◽  
Stanley J. Klepeis

The continuing reduction in the sizes of features of interest for integrated circuit failure analysis requires greater precision in transmission electron microscopy (TEM) sample preparation. With minimum feature sizes approaching 0.5 μm, the mere finding of such a feature at a polished edge, let alone preparing a TEM sample containing it becomes a formidable task. The required substantial thinning also increases the risk of loss of what may be a unique sample.We present in this paper a technique that allows localized thinning of cross-sectional TEM samples using a focused ion beam (FIB) machine. Standard preparation techniques are used to make a cross-sectional TEM sample that would otherwise be too thick to be very useful for TEM analysis. This sample is then placed in the FIB machine, which is used as a micromachining tool. No special surface preparation is necessary and the secondary electron signal generated by the ion beam provides an image that can be used to locate the feature of interest.


Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
J.T. Harbaugh ◽  
M. Boccabella ◽  
...  

Abstract The sub-nanometer resolution that transmission electron microscopy (TEM) provides is critical to the development and fabrication of advanced integrated circuits. TEM specimens are usually prepared using the focused ion beam, which can cause gallium-induced artifacts and amorphization. This work presents the use of a concentrated argon ion beam for reproducible TEM specimen preparation using automatic milling termination and targeted ion milling of device features; the result is high-quality and electron-transparent specimens of less than 30 nm. Such work is relevant for semiconductor product development and failure analysis.


1998 ◽  
Vol 4 (S2) ◽  
pp. 862-863 ◽  
Author(s):  
B. Foran ◽  
F. Shaapur ◽  
V. Blaschke

Sample preparation for transmission electron microscopy (TEM) has been a source of speculation with regards to potential for the creation of artifacts which may confound data gleaned from TEM analysis. For semiconductor integrated circuit (IC) materials characterization, the most common sample preparatory methods are based on final thinning by ion beam milling. The latest shift towards Copper / low dielectric constant (k) composite systems in the semiconductor IC industry provides several challenges for TEM sample preparation resulting from differences in milling rates and materials properties for neighboring features.In conjunction with process development for integration of Cu / low-k materials, conducted at SEMATECH, we have systematically studied the effects of TEM sample preparation by ion milling in order to search for artifacts that could result from sample thinning procedures. For this purpose we have studied wafers with patterned copper lines isolated by a low-k polymer. One sample was stressed by thermal and electronic bias, while a second was subjected to only thermal stress.


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