Cross-sectional Specimen Preparation of Fragile Failure Location in Thin-Film Transistors Using Focused Ion Beam Etching and Transmission Electron Microscope

Author(s):  
N. Miura ◽  
K. Tsujimato ◽  
R. Kanehara ◽  
N. Tsutsui ◽  
S. Tsuji

Abstract This paper describes how faulty thin-film transistors (TFTs) having fragile structures in themselves can be characterized by cross-sectional transmission electron microscopy (X-TEM) through the achievement of pinpoint accuracy in focused ion beam (FIB) etching. We demonstrate X-TEM analysis for faulty TFTs caused by mechanical damages, microvoid in their multilayers and long aluminum whiskers growing from the electrodes. X-TEM specimen were prepared by FIB etching without losing unique structures owing to fragile locations. Cross-sectional bright-field TEM micrographs clearly showed the details of cross sectional structure of fragile location. This pin-point X-TEM is quite helpful to identify faults and to reveal root causes of failures.

1996 ◽  
Vol 466 ◽  
Author(s):  
K. Kuroda ◽  
S. Tsuji ◽  
Y. Hayashi ◽  
H. Saka

ABSTRACTHydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) are now widely used as elements for active matrix liquid crystal displays. The nanometer-scale multilayered structure of a-Si:H TFTs has been characterized by cross-sectional transmission electron microscopy (TEM). The discrete layer construction of a faulty TFTs and the generation of defects during manufacturing processes have been investigated. A combination of focused ion beam (FIB) etching and cross-sectional TEM leads to a successful failure analysis. A contamination layer with a thickness of 10–30 nm and microvoids inside multilayers are identified in faulty TFTs. An a-Si layer on silicon nitride (SiNx) is crystallized during TEM observation. Electron energy loss spectroscopy analysis indicates that the diffusion of nitrogen into a-Si layer causes the crystallization.


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.


2000 ◽  
Vol 6 (3) ◽  
pp. 218-223
Author(s):  
Toshie Yaguchi ◽  
Takeo Kamino ◽  
Mitsumasa Sasaki ◽  
Gerard Barbezat ◽  
Ryoichi Urao

Abstract A focused ion beam (FIB) technique was applied to cross-sectional specimen preparation to observe an interface between a plasma sprayed coating and an aluminum (Al) substrate by transmission electron microscopy (TEM). The surface of the sprayed coating film has a roughness of several tens of microns. Sputter rates for the coating film and the substrate are greatly different. The rough surface and the difference in sputter rate cause problems in making TEM specimens with smooth side walls. The top surface of the coating film was planerized by the FIB before fabricating the TEM specimen. The interfaces were investigated by TEM and energy-dispersive X-ray (EDX) analysis. The TEM observation revealed that there is a 10 nm thick amorphous layer at the interface between the coating film and substrate. The coating film consists of two kinds of sublayers with bright and dark contrast. The bright contrast sublayers were amorphous layers with thickness of 2~10 nm. The Al/Fe X-ray intensity ratio was larger in bright contrast sublayers than that in dark contrast sublayers.


1999 ◽  
Vol 5 (S2) ◽  
pp. 908-909
Author(s):  
J.L. Drown-MacDonald ◽  
B.I. Prenitzer ◽  
T.L. Shofner ◽  
L.A. Giannuzzi

Focused Ion Beam (FIB) specimen preparation for both scanning and transmission electron microscopy (SEM and TEM respectively) has seen an increase in usage over the past few years. The advantage to the FIB is that site specific cross sections (or plan view sections) may be fabricated quickly and reproducibly from numerous types of materials using a finely focused beam of Ga+ ions [1,2]. It was demonstrated by Prenitzer et al. that TEM specimens may be acquired from individual Zn powder particles by employing the FIB LO specimen preparation technique [3]. In this paper, we use the FIB LO technique to prepare TEM specimens from Mount Saint Helens volcanic ash.Volcanic ash from Mount Saint Helens was obtained at the Microscopy and Microanalysis 1998 meeting in Atlanta. TEM analysis of the ash was performed using the FIB lift out technique [1]. Ash powders were dusted onto an SEM sample stud that had been coated with silver paint.


1990 ◽  
Vol 199 ◽  
Author(s):  
Kyung-ho Park

ABSTRACTA procedure for preparing cross-sectional TEM specimens by focused ion beam etching (FIB) of specific regions on an integrated circuit chip is outlined. The investigation of the morphology, structure and local chemistry of precisely selected regions of semiconductor devices becomes increasingly important since the lateral dimensions and layer thickness of device structures are continually being reduced. The standard technique of preparing specimens for TEM, whether planar or cross-sectional, cannot select particular small regions. Some techniques and a number of tools and fixtures have been proposed which allow us to prepare TEM specimen of prespecified locations in complex devices. Most of these techniques, however, are still very difficult, tedious process and time consuming.A new technique has been proposed recently involving the use of FIB. The technique ensures that the preselected area of submicron scale will be located in the electron transparent section used for TEM imaging, in preparation turn-around time of about two hours. The TEM imaging of specific contacts via hole in a VLSI chip is illustrated.


1999 ◽  
Vol 5 (5) ◽  
pp. 365-370 ◽  
Author(s):  
Toshie Yaguchi ◽  
Takeo Kamino ◽  
Tohru Ishitani ◽  
Ryoichi Urao

A new method for transmission electron microscope (TEM) specimen preparation using a focused ion beam (FIB) system that results in a lower rate of gallium (Ga) implantation has been developed. The method was applied to structural and analytical studies of composite materials such as silicon (Si)-devices and magneto-optical disk. To protect the specimens against Ga ion irradiation, amorphous tungsten (W) was deposited on the surface of the specimen prior to FIB milling. The deposition was quite effective in reducing the Ga implantation rate, and energy-dispersive X-ray (EDX) analysis of these specimens detected 0.3Ð1.5% Ga incorporated in the thinned area. FIB milling times for these specimens were 1.5Ð2 hr. Although the milling rate was high, all the materials were properly prepared for TEM study, and clear crystal lattice images were observed on all specimens.


1999 ◽  
Vol 7 (2) ◽  
pp. 12-15 ◽  
Author(s):  
Lucille A. Giannuzzi ◽  
Richard Young ◽  
Pete Carleson

AbstractDriven by the analytical needs of microelectronics, magnetic media and micro-fabrication industries, focused ion beam (FIB) systems are now capable of milling and manipulating samples for the analysis of microstructure features having dimensions of 180 nm or less, A technique for locating and extracting site specific specimens for examination by transmission electron microscopy (TEM) has been developed. An identified feature can be located and precisely milled with an FIB system from two sides to prepare an ultrathin sample, and then extracted from the region with a glass rod micromanipulator onto a grid for TEM analysis. This specimen preparation method has been applied to semiconductor failure analysis and to the study of metallic and ceramic microsiructures with irregular topographies and complex mufti-layered components.


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