Challenges and Solutions in Preparation for High Resolution Failure Analysis of Power Electronics

2014 ◽  
Vol 2014 (1) ◽  
pp. 000338-000342
Author(s):  
Robert Klengel ◽  
Sandy Klengel ◽  
Bianca Böttge

The high-resolution failure analysis of power electronic devices is very challenging, as relatively large features have to be accessed and analyzed with nanometer resolution. Recently new tools have been introduced for fast and efficient sample preparation of stacked devices and complex packages. One of them is the focused ion beam (FIB) technique using a high energy Xenon Plasma-FIB. This paper outlines preparation issues needed to find the physics of failure of large and complex devices as used in power electronics. Different methods like high throughput Plasma FIB preparation to combined Laser-FIB preparation are compared. Additionally an innovative mechanical preparation technique developed for interface defect preparation of power electronic materials will be introduced. Within the paper selected case studies regarding reliability investigations and failure analysis are presented for example on silver sinter layers and bond wire contacts done by high resolution Transmission Electron Microscopy (TEM). In addition, an assessment of the analysis throughput increase, of new extended application ranges and current limitations will be given.

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.


1998 ◽  
Vol 523 ◽  
Author(s):  
Paul D. Brown ◽  
Colin J. Humphreys

AbstractThe characterisation of semiconductor thin films and device structures increasingly requires the use of a variety of complementary electron microscope-based techniques as feature sizes decrease. We illustrate how layer electrical and structural properties can be correlated: firstly averaged over the bulk and then on the individual defect scale, e.g. scanning transmission electron beam induced conductivity can be used to image the recombination activity of orthogonal <110> misfit dislocations within relaxed MBE grown Si/Si1-xGex/Si(001) heterostructures on the sub-micrometre scale. There is also need for improved understanding of sample preparation procedures and imaging conditions such that materials issues relevant to ULSI development can be addressed without hindrance from artefact structures. Hence, we consider how point defects interact under the imaging electron beam and the relative merits of argon ion milling, reactive ion beam etching, focused ion beam milling and plasma cleaning when used for TEM sample preparation. Advances in sample preparation procedures must also respect inherent problems such as thin foil surface relaxation effects, e.g. cleaved wedge geometries are more appropriate than conventional cross-sections for the quantitative characterisation of δ-doped layers. Choice of the right imaging technique for the problem to be addressed is illustrated through consideration of polySi/Si emitter interfaces within bipolar transistor structures. The development of microscopies for the rapid analysis of electronic materials requires wider consideration of non-destructive techniques of assessment, e.g. reflection high energy electron diffraction in a modified TEM is briefly described.


Author(s):  
G. Benstetter ◽  
G. Bomberger ◽  
P. Coutu ◽  
R. Danyew ◽  
R. Douse

Abstract Reducing the cell size of DRAMs in 0.35 micron and follow-on technologies requires failure analysis techniques that can analyze single storage node trench capacitors on both test sites and actual product. A combination of electrical microprobing, probeless voltage contrast and physical delayering procedures, all based on focused- ion-beam (FIB) techniques, are described. Because of precise fail localization, high resolution scanning electron microscope (SEM) imaging enables the distinction between process defects and intrinsic breakdowns of node dielectric defects. Isolated storage cells can be electrically characterized by depositing small probe pads, using FIB for contact hole milling and probe-pad deposition. To localize trench capacitors with a leakage path to the surrounding substrate, the trenches are isolated by mechanical polishing and probeless voltage contrast in the FIB tool. Failing trench capacitors can be marked in the FIB tool. Physical isolation of leaking trench capacitors can be achieved by recessing the adjacent trench capacitors, with the FIB used for milling and a subsequent wet chemical removal added for the remaining substrate material. Alternatively, trench capacitors can be inspected from the backside when stabilized by a quartz deposition on top, followed by mechanical polishing from the side and a wet chemical etching of the remaining substrate material. In both cases, the dielectric of the node trench capacitors can be inspected by high resolution SEMs and the defect areas precisely analyzed.


1991 ◽  
Vol 254 ◽  
Author(s):  
R. Clampitt ◽  
G. G. Ross ◽  
M. Phelan ◽  
S. A. Davies

AbstractImprovements in specimen preparation for TEM analysis are being constantly sought, particularly in the study of microelectronics' materials and in failure analysis of devices. We describe here a compact commercial system capable of thinning (milling) selected regions of a specimen by means of a scanned focused ion beam of sub-micron spatial resolution.


2013 ◽  
Vol 19 (S5) ◽  
pp. 33-37 ◽  
Author(s):  
Yoon Huh ◽  
Ki Jung Hong ◽  
Kwang Soo Shin

AbstractFocused ion beam (FIB) milling using high-energy gallium ions is widely used in the preparation of specimens for transmission electron microscopy (TEM). However, the energetic ion beam induces amorphization on the edge of specimens during milling, resulting in a mischievous influence on the clearness of high-quality transmission electron micrographs. In this work, the amorphization induced by the FIB milling was investigated by TEM for three kinds of materials, metallic materials in bulk shape, and semiconductive and electronic ceramic materials as a substrate for the deposition of thin films.


Author(s):  
Natsuko Asano ◽  
Shunsuke Asahina ◽  
Natasha Erdman

Abstract Voltage contrast (VC) observation using a scanning electron microscope (SEM) or a focused ion beam (FIB) is a common failure analysis technique for semiconductor devices.[1] The VC information allows understanding of failure localization issues. In general, VC images are acquired using secondary electrons (SEs) from a sample surface at an acceleration voltage of 0.8–2.0 kV in SEM. In this study, we aimed to find an optimized electron energy range for VC acquisition using Auger electron spectroscopy (AES) for quantitative understanding.


Author(s):  
Becky Holdford

Abstract On mechanically polished cross-sections, getting a surface adequate for high-resolution imaging is sometimes beyond the analyst’s ability, due to material smearing, chipping, polishing media chemical attack, etc.. A method has been developed to enable the focused ion beam (FIB) to re-face the section block and achieve a surface that can be imaged at high resolution in the scanning electron microscope (SEM).


Author(s):  
Max L. Lifson ◽  
Carla M. Chapman ◽  
D. Philip Pokrinchak ◽  
Phyllis J. Campbell ◽  
Greg S. Chrisman ◽  
...  

Abstract Plan view TEM imaging is a powerful technique for failure analysis and semiconductor process characterization. Sample preparation for near-surface defects requires additional care, as the surface of the sample needs to be protected to avoid unintentionally induced damage. This paper demonstrates a straightforward method to create plan view samples in a dual beam focused ion beam (FIB) for TEM studies of near-surface defects, such as misfit dislocations in heteroepitaxial growths. Results show that misfit dislocations are easily imaged in bright-field TEM and STEM for silicon-germanium epitaxial growth. Since FIB tools are ubiquitous in semiconductor failure analysis labs today, the plan view method presented provides a quick to implement, fast, consistent, and straightforward method of generating samples for TEM analysis. While this technique has been optimized for near-surface defects, it can be used with any application requiring plan view TEM analysis.


Author(s):  
Zixiao Pan ◽  
Wei Wei ◽  
Fuhe Li

Abstract This paper introduces our effort in failure analysis of a 200 nm thick metal interconnection on a glass substrate and covered with a passivation layer. Structural damage in localized areas of the metal interconnections was observed with the aid of focused ion beam (FIB) cross-sectioning. Laser ablation inductively coupled plasma mass spectroscopy (LA ICP-MS) was then applied to the problematic areas on the interconnection for chemical survey. LA ICP-MS showed direct evidence of localized chemical contamination, which has likely led to corrosion (or over-etching) of the metal interconnection and the assembly failure. Due to the high detection sensitivity of LA ICP-MS and its compatibility with insulating material analysis, minimal sample preparation is required. As a result, the combination of FIB and LA ICP-MS enabled successful meso-scale failure analysis with fast turnaround and reasonable cost.


Author(s):  
Po Fu Chou ◽  
Li Ming Lu

Abstract Dopant profile inspection is one of the focused ion beam (FIB) physical analysis applications. This paper presents a technique for characterizing P-V dopant regions in silicon by using a FIB methodology. This technique builds on published work for backside FIB navigation, in which n-well contrast is observed. The paper demonstrates that the technique can distinguish both n- and p-type dopant regions. The capability for imaging real sample dopant regions on current fabricated devices is also demonstrated. SEM DC and FIB DC are complementary methodologies for the inspection of dopants. The advantage of the SEM DC method is high resolution and the advantage of FIB DC methodology is high contrast, especially evident in a deep N-well region.


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