Red Phosphorous Induced Shorts in Plastic Packages

Author(s):  
Rafael Huerta ◽  
Nevil Wu

Abstract Red phosphorous is one of the inorganic phosphorous compounds used as a flame retardant in microelectronic applications. One of the concerns is a red phosphorus induced pin-to-pin short in the molding compound. This paper discusses the red phosphorous-induced shorts in a 100 Lead TQFP (14x20x1.4mm) plastic package. The devices first failed on boards in the field. After de-soldering them from the boards, the devices were tested and found to have resistive pin-to-pin shorts. Common failure analysis techniques, including parallel lapping, cross sectioning, and X-ray, failed to reveal the resistive shorts and the shorting mechanism. Removing the molding compound by means of a wet chemical etching method using sulfuric acid on a hot plate worked very well and enabled to expose particles in three dimensions. It was concluded that the resistive shorts were not necessarily due to a single large phosphorous particle, but due to small and fragmented pieces of phosphorous.

Author(s):  
Ronald R. Hylton

Abstract This paper describes the electrical signatures and failure analysis techniques used to identify plastic encapsulated devices that have failed due to silver migration. This migration, which produces resistive leakages between adjacent pins, has been associated with molding compounds that utilize red phosphorous as a flame retardant material. A description of the failure mechanism is also presented.


Clay Minerals ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 289-292 ◽  
Author(s):  
H. Faghihian ◽  
M. Pirouzi

AbstractSeparation of nitrogen, the major impurity of natural gas, is necessary for quality improvement of the gas. In this study, purified and some ion-exchanged forms of clinoptilolite were used to separate N2 from natural gas. Competitive adsorption of mixtures of N2, CH4 and C2H6 by Cu2+ (Cu-Cp)-, Zn2+ (Zn-Cp)-, Ni2+ (Ni-Cp)- and Mn2+ (Mn-Cp)-exchanged samples was studied at different pressures and ambient temperature. Among the cations studied, Cu2+ has the lowest selectivity towards N2. Samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, BET N2 adsorption and wet chemical analysis techniques.


1997 ◽  
Vol 119 (4) ◽  
pp. 247-254 ◽  
Author(s):  
S. Han ◽  
K. K. Wang ◽  
D. L. Crouthamel

In this study, the wire-sweep problem has been studied by performing experiments using a commercial-grade epoxy molding compound, a real chip assembly, and an industrial encapsulation process. After encapsulating the chip, the deformed wire shape inside the plastic package has been determined by X-ray scanning. A procedure for the wire-sweep calculation during encapsulation process has been developed. The wire sweep values have been calculated using this procedure with material properties measured from experiments. The calculated wire-sweep values are compared with experimental values measured at different mold temperatures, fill times, and cavities. In most cases, the calculated values are in good agreement with the experimental values.


Author(s):  
Dima A. Smolyansky

Abstract The visual nature of Time Domain Reflectometry (TDR) makes it a very natural technology that can assist with fault location in BGA packages, which typically have complex interweaving layouts that make standard failure analysis techniques, such as acoustic imaging and X-ray, less effective and more difficult to utilize. This article discusses the use of TDR for package failure analysis work. It analyzes in detail the TDR impedance deconvolution algorithm as applicable to electronic packaging fault location work, focusing on the opportunities that impedance deconvolution and the resulting true impedance profile opens up for such work. The article examines the TDR measurement accuracy and the comparative package failure analysis, and presents three main considerations for package failure analysis. It also touches upon the goal and the task of the failure analysts and TDR's specific signatures for the open and short connections.


1994 ◽  
Vol 58 (391) ◽  
pp. 307-314 ◽  
Author(s):  
Mizuhiko Akizuki ◽  
Hirotugu Nisidoh ◽  
Yasuhiro Kudoh ◽  
Tomohiro Watanabe ◽  
Kazuo Kurata

AbstractA study of apatite crystals from the Asio mine, Japan, showed sectoral texture related to the growth of the crystal, and with optically biaxial properties within the sectors. Wet chemical analysis gave a composition Ca5(PO4)3(F0.64,OH0.38,Cl0.01)1.03 for the specimen.Additional diffraction spots were not observed in precession and oscillation X-ray photographs and electron diffraction photographs. Since the internal textures correlate with the surface growth features, it is suggested that the internal textures and the unusual optical properties were produced during nonequilibrium crystal growth. The fluorine/hydroxyl sites in hexagonal apatite are symmetrically equivalent in the solid crystal but, at a growth surface, this equivalence may be lost, resulting in a reduction of crystal symmetry. Heating of the apatite to about 850°C results in the almost complete disappearance of the optical anomalies due to disordering, which may be related to the loss of hydroxyl from the crystal.


Author(s):  
Vahid Zabihi ◽  
Mohammad Hasan Eikani ◽  
Mehdi Ardjmand ◽  
Seyed Mahdi Latifi ◽  
Alireza Salehirad

Abstract One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.


2021 ◽  
Vol 7 (3) ◽  
pp. eabc8660
Author(s):  
F. Mirani ◽  
A. Maffini ◽  
F. Casamichiela ◽  
A. Pazzaglia ◽  
A. Formenti ◽  
...  

Among the existing elemental characterization techniques, particle-induced x-ray emission (PIXE) and energy-dispersive x-ray (EDX) spectroscopy are two of the most widely used in different scientific and technological fields. Here, we present the first quantitative laser-driven PIXE and laser-driven EDX experimental investigation performed at the Centro de Láseres Pulsados in Salamanca. Thanks to their potential for compactness and portability, laser-driven particle sources are very appealing for materials science applications, especially for materials analysis techniques. We demonstrate the possibility to exploit the x-ray signal produced by the co-irradiation with both electrons and protons to identify the elements in the sample. We show that, using the proton beam only, we can successfully obtain quantitative information about the sample structure through laser-driven PIXE analysis. These results pave the way toward the development of a compact and multifunctional apparatus for the elemental analysis of materials based on a laser-driven particle source.


1979 ◽  
Vol 23 ◽  
pp. 333-339
Author(s):  
S. K. Gupta ◽  
B. D. Cullity

Since the measurement of residual stress by X-ray diffraction techniques is dependent on the difference in angle of a diffraction peak maximum when the sample is examined consecutively with its surface at two different angles to the diffracting planes, it is important that these diffraction angles be obtained precisely, preferably with an accuracy of ± 0.01 deg. 2θ. Similar accuracy is desired in precise lattice parameter determination. In such measurements, it is imperative that the diffractometer be well-aligned. It is in the context of diffractometer alignment with the aid of a silicon powder standard free of residual stress that the diffraction peak analysis techniques described here have been developed, preparatory to residual stress determinations.


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