The Application of FIB Voltage-Contrast Technique Combining with TEM on Subtle Defect Analysis: Via Delamination After TC

Author(s):  
X. Yang ◽  
X. Song

Abstract Novel Focused Ion Beam (FIB) voltage-contrast technique combined with TEM has been used in this study to identify a certain subtle defect mechanism that caused reliability stress failures of a new product. The suspected defect was first isolated to a unique via along the row through electrical testing and layout analysis. Static voltage contrast of FIB cross-section was used to confirm the suspected open defect at the via. Precision Transmission Electron Microscope (TEM) was then used to reveal the detail of the defect. Based on the result, proper process changes were implemented. The failure mode was successfully eliminated and the reliability of the product was greatly improved.

Author(s):  
J. Douglass ◽  
T. D. Myers ◽  
F. Tsai ◽  
R. Ketcheson ◽  
J. Errett

Abstract This paper describes how the authors used a combination of focused ion beam (FIB) microprobing, transmission electron microscopy (TEM), and data and process analysis to determine that localized water residue was causing a 6% yield loss at die sort.


Author(s):  
H. J. Bender ◽  
R. A. Donaton

Abstract The characteristics of an organic low-k dielectric during investigation by focused ion beam (FIB) are discussed for the different FIB application modes: cross-section imaging, specimen preparation for transmission electron microscopy, and via milling for device modification. It is shown that the material is more stable under the ion beam than under the electron beam in the scanning electron microscope (SEM) or in the transmission electron microscope (TEM). The milling of the material by H2O vapor assistance is strongly enhanced. Also by applying XeF2 etching an enhanced milling rate can be obtained so that both the polymer layer and the intermediate oxides can be etched in a single step.


Author(s):  
Dirk Doyle ◽  
Lawrence Benedict ◽  
Fritz Christian Awitan

Abstract Novel techniques to expose substrate-level defects are presented in this paper. New techniques such as inter-layer dielectric (ILD) thinning, high keV imaging, and XeF2 poly etch overflow are introduced. We describe these techniques as applied to two different defects types at FEOL. In the first case, by using ILD thinning and high keV imaging, coupled with focused ion beam (FIB) cross section and scanning transmission electron microscopy (STEM,) we were able to judge where to sample for TEM from a top down perspective while simultaneously providing the top down images giving both perspectives on the same sample. In the second case we show retention of the poly Si short after removal of CoSi2 formation on poly. Removal of the CoSi2 exposes the poly Si such that we can utilize XeF2 to remove poly without damaging gate oxide to reveal pinhole defects in the gate oxide. Overall, using these techniques have led to 1) increased chances of successfully finding the defects, 2) better characterization of the defects by having a planar view perspective and 3) reduced time in localizing defects compared to performing cross section alone.


Author(s):  
H. Lorenz ◽  
C. Engel

Abstract Due to the continuously decreasing cell size of DRAMs and concomitantly diminishing thickness of some insulating layers new failure mechanisms appear which until now had no significance for the cell function. For example high resistance leakage paths between closely spaced conductors can lead to retention problems. These are hard to detect by electrical characterization in a memory tester because the involved currents are in the range of pA. To analyze these failures we exploit the very sensitive passive voltage contrast of the Focused Ion Beam Microscope (FIB). The voltage contrast can further be enhanced by in-situ FIB preparations to obtain detailed information about the failure mechanism. The first part of this paper describes a method to detect a leakage path between a borderless contact on n-diffusion and an adjacent floating gate by passive voltage contrast achieved after FIB circuit modification. In the second part we will demonstrate the localization of a DRAM trench dielectric breakdown. In this case the FIB passive voltage contrast technique is not limited to the localization of the failing trench. We can also obtain the depth of the leakage path by selective insitu etching with XeF2 stopped immediately after a voltage contrast change.


2011 ◽  
Vol 17 (6) ◽  
pp. 889-895 ◽  
Author(s):  
Lynne M. Gignac ◽  
Surbhi Mittal ◽  
Sarunya Bangsaruntip ◽  
Guy M. Cohen ◽  
Jeffrey W. Sleight

AbstractThe ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.


1995 ◽  
Vol 380 ◽  
Author(s):  
C. Deng ◽  
J. C. Wu ◽  
C. J. Barbero ◽  
T. W. Sigmon ◽  
M. N. Wybourne

ABSTRACTA fabrication process for sub-100 nm Ge wires on Si substrates is reported for the first time. Wires with a cross section of 6 × 57 nm2 are demonstrated. The wire structures are analyzed by atomic force (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Sample preparation for TEM is performed using a novel technique using both pre and in situ deposition of multiple protection layers using a Focused Ion Beam (FIB) micromachining system.


Author(s):  
S.L. Ting ◽  
P.K. Tan ◽  
I. Withana ◽  
H. Tan ◽  
C.Q. Chen

Abstract Passive voltage contrast (PVC) is widely used to detect underlying connectivity issues between metals based on the brightness of upper metals using scanning electron microscopy (SEM) or focused ion beam (FIB). [1] However, it cannot be applied in all cases due to the uniqueness of each case where brightness alone is insufficient to tell leakage location. In this study, propose a simple technique using platinum (Pt) marking as a circuit edit (CE) technique to alter metal PVC to identify the actual leakage location. Conventional SEM and PVC contrast imaging are unable to pinpoint exact defects without data confirming the leakage from nano-probing such as Atomic Force Probing (AFP) or SEM base nano-probing (NP) [2]. Using this method, we can improve the analysis cycle time by direct analysts the defective location in SEM, while also saving tool cost.


2002 ◽  
Vol 738 ◽  
Author(s):  
Heinz D. Wanzenboeck ◽  
Stefan Harasek ◽  
Wolfgang Brezna ◽  
Alois Lugstein ◽  
Helmut Langfischer ◽  
...  

ABSTRACTImaging critical features by using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) provides a versatile approach for nanostructure characterization. The combination of focused ion beam (FIB) technology for exposing defective sites beneath the surface is shown. Reliability testing and defect analysis by localized characterization of multilayered structures is demonstrated. TEM-imaging of a transistor gate with a locally confined radiation damage demonstrates target preparation by FIB yielding high-resolution TEM samples. The TEM imaging requires a longer sample preparation but provides high image quality (TEM). Investigation of materials previously processed with FIB revealed amorphization damage by the high energetic Ga-ion beam. This damage layer with a thickness in the range of 50 to 100 nm was confirmed in simulation. This disadvantageous damage by amorphization originating from FIB preparation of the cross-section could be removed by soft sputtering with a 250 V Ar+ ion beam. This combined method using FIB for microsample preparation and TEM for imaging and analysis was proven to be a powerful tool the exploitation of nanostructured devices and for defect analysis on a highly localized scale.


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