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16 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2 [Next/Last]

Instruments / Technical Area	Publication Details	Published
B16-Test Beamline	X-ray diffraction imaging of fully packaged n–p–n transistors under accelerated ageing conditions Brian K. Tanner , Andreas Danilewsky , Patrick J. Mcnally Journal Of Applied Crystallography 55 DOI: 10.1107/S1600576722007142 Diamond Proposal Number(s): [23563] Open Access Show Abstract ▼ Abstract: X-ray diffraction imaging was used to monitor the local strains that developed around individual n–p–n bipolar transistors within fully encapsulated packages under conditions of extremely high forward bias to simulate accelerated ageing. Die warpage associated with the packaging was observed to relax systematically as the polymer became viscous due to the temperature rise associated with the dissipation of heat in the transistor. The direct image size and intensity from the individual transistors were interpreted in terms of a model in which local thermal expansion is treated as a cylindrical inclusion of distorted material, contrast arising principally from lattice tilt. The extension of the thermal strain image along the emitter with increasing power dissipation was ascribed to the effect of current crowding in the emitter region. Weaker large-area contrast associated with the base–collector region was interpreted as arising from the smaller change in effective misorientation at the high X-ray energy of thermal lattice dilation in the base region.	Oct 2022
B16-Test Beamline	X-ray imaging of silicon die within fully packaged semiconductor devices Brian K. Tanner , Patrick J. Mcnally , Andreas N. Danilewsky Powder Diffraction DOI: 10.1017/S088571562100021X Open Access Show Abstract ▼ Abstract: X-ray diffraction imaging (XRDI) (topography) measurements of silicon die warpage within fully packaged commercial quad-flat no-lead devices are described. Using synchrotron radiation, it has been shown that the tilt of the lattice planes in the Analog Devices AD9253 die initially falls, but after 100 °C, it rises again. The twist across the die wafer falls linearly with an increase in temperature. At 200 °C, the tilt varies approximately linearly with position, that is, displacement varies quadratically along the die. The warpage is approximately reversible on cooling, suggesting that it has a simple paraboloidal form prior to encapsulation; the complex tilt and twisting result from the polymer setting process. Feasibility studies are reported, which demonstrate that a divergent beam and quasi-monochromatic radiation from a sealed X-ray tube can be used to perform warpage measurements by XRDI in the laboratory. Existing tools have limitations because of the geometry of the X-ray optics, resulting in applicability only to simple warpage structures. The necessary modifications required for use in situations of complex warpage, for example, in multiple die interconnected packages are specified.	Mar 2021
B16-Test Beamline	In-operando X-ray diffraction imaging of thermal strains in fully packaged silicon devices B. K. Tanner , R. K. Vijayaraghavan , B. Roarty , A. N. Danilewsky , P. J. Mcnally Microelectronics Reliability 99, 232-238 DOI: 10.1016/j.microrel.2019.06.006 Diamond Proposal Number(s): [17275] Show Abstract ▼ Abstract: The application of X-ray Diffraction Imaging to measure in operando thermal strains at individually powered components within fully packaged LM3046 silicon devices is described. It is shown that as the local strains increase with power dissipated, above a threshold power loading, the associated region of enhanced X-ray intensity increases monotonically. The changes in contrast in the image are discussed. Asterism in section topographs changes sign as the slit is moved across the component, consistent with lattice strain around the device due to the thermal expansion. Above a threshold power, this asterism increases linearly with power loading. By simultaneous measurement of the package surface temperature it is possible to deduce the local component temperature from the extent of the contrast in the X-ray image.	Aug 2019
B16-Test Beamline	Direct observation of stress relaxation process in 4H-SiC homoepitaxial layers via in situ synchrotron x-ray topography Jian Qiu Guo , Yu Yang , Balaji Raghothamachar , Michael Dudley , Swetlana Weit , Andreas N. Danilewsky , Patrick J. Mcnally , Brian K. Tanner Materials Science Forum 924, 176 - 179 DOI: 10.4028/www.scientific.net/MSF.924.176 Diamond Proposal Number(s): [13464] Show Abstract ▼ Abstract: During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely believed that an interfacial dislocation is created by the glide of a mobile segment of a basal plane dislocation (BPD) in the substrate or epilayer towards the interface, leaving a trailing edge component right at the interface. However, direct observation of such mechanisms has not been made in SiC before. In this work, we present an in situ study of the stress relaxation process, in which a specimen cut from a commercial 4H-SiC homoepitaxial wafer undergoes the stress relaxation process during a high-temperature heat treatment while sequential synchrotron white beam X-ray topographs were recorded simultaneously. Based on the dynamic observation of this process, it can be concluded that thermal stress plays a role in the relaxation process while the increased misfit strain at elevated temperature most likely drives the formation of an interfacial dislocation.	Jun 2018
B16-Test Beamline	In situ synchrotron x-ray topography observation of double-ended Yu Yang , Jian Qiu Guo , Balaji Raghothamachar , Michael Dudley , Swetlana Weit , Andreas N. Danilewsky , Patrick J. Mcnally , Brian K. Tanner Materials Science Forum 924, 172 - 175 DOI: 10.4028/www.scientific.net/MSF.924.172 Diamond Proposal Number(s): [13464] Show Abstract ▼ Abstract: We present in-situ observations of the dynamical operation of multiple double-ended Frank-Read dislocation sources in a PVT-grown 4H-SiC wafer under thermal gradient stresses. The nucleation of these sources is facilitated by a specific configuration consisting of one basal plane dislocation (BPD) segment pinned by two threading edge dislocations (TEDs). This configuration is formed during PVT crystal growth by deflection of TEDs on to the basal planes by macrosteps and re-deflection of resulting BPDs back into TEDs. Under the influence of thermal gradient stresses induced by heating inside a double ellipsoidal mirror furnace, the pinned BPD segment glides and activates dislocation multiplication by the double Frank-Read source mechanism. A more intricate mechanism of swapping of TED pinning points between Frank-Read sources lying on the same basal plane is identified, enabling one dislocation loop to effectively “pass through” the other dislocations on the same basal plane.	Jun 2018
B16-Test Beamline	Quantitative imaging of the stress/strain fields and generation of macroscopic cracks from indents in silicon Brian K. Tanner , David Allen , Jochen Wittge , Dany Danilewsky , Jorge Garagorri , Eider Gorostegui-Colinas , M. Reyes Elizalde , Patrick J. Mcnally Crystals 7 DOI: 10.3390/cryst7110347 Diamond Proposal Number(s): [6257, 3232] Open Access Show Abstract ▼ Abstract: The crack geometry and associated strain field around Berkovich and Vickers indents on silicon have been studied by X-ray diffraction imaging and micro-Raman spectroscopy scanning. The techniques are complementary; the Raman data come from within a few micrometres of the indentation, whereas the X-ray image probes the strain field at a distance of typically tens of micrometres. For example, Raman data provide an explanation for the central contrast feature in the X-ray images of an indent. Strain relaxation from breakout and high temperature annealing are examined and it is demonstrated that millimetre length cracks, similar to those produced by mechanical damage from misaligned handling tools, can be generated in a controlled fashion by indentation within 75 micrometres of the bevel edge of 200 mm diameter wafers.	Nov 2017
B16-Test Beamline	Nondestructive X-ray diffraction measurement of warpage in silicon dies embedded in integrated circuit packages B. K. Tanner , A. N. Danilewsky , R. K. Vijayaraghavan , A. Cowley , P. J. Mcnally Journal Of Applied Crystallography 50 DOI: 10.1107/S1600576717003132 Diamond Proposal Number(s): [7983, 8526, 9471, 12771] Open Access Show Abstract ▼ Abstract: Transmission X-ray diffraction imaging in both monochromatic and white beam section mode has been used to measure quantitatively the displacement and warpage stress in encapsulated silicon devices. The displacement dependence with position on the die was found to agree well with that predicted from a simple model of warpage stress. For uQFN microcontrollers, glued only at the corners, the measured misorientation contours are consistent with those predicted using finite element analysis. The absolute displacement, measured along a line through the die centre, was comparable to that reported independently by high-resolution X-ray diffraction and optical interferometry of similar samples. It is demonstrated that the precision is greater than the spread of values found in randomly selected batches of commercial devices, making the techniques viable for industrial inspection purposes.	Apr 2017
B16-Test Beamline	B-Spline X-Ray Diffraction Imaging — Rapid non-destructive measurement of die warpage in ball grid array packages A. Cowley , A. Ivankovic , C. S. Wong , N. S. Bennett , A. N. Danilewsky , M. Gonzalez , V. Cherman , B. Vandevelde , I. De Wolf , P. J. Mcnally Microelectronics Reliability 59, 108 - 116 DOI: 10.1016/j.microrel.2015.12.030 Diamond Proposal Number(s): [8526, 9479] Show Abstract ▼ Abstract: Next generation “More than Moore” integrated circuit (IC) technology will rely increasingly on the benefits attributable to advanced packaging (www.itrs.net[1]). In these increasingly heterogeneous systems, the individual semiconductor die is becoming much thinner (25 to 50 μm, typically) and multiple dies can be stacked upon each other. It is difficult to assess non-destructively, non-invasively and in situ the stress or warpage of the semiconductor die inside these chip packages and conventional approaches tend to monitor the warpage of the package rather than the die. This paper comprises an account of a relatively new technique, which we call B-Spline X-Ray Diffraction Imaging (B-XRDI) and its application, in this instance, to the non-destructive mapping of Si semiconductor die lattice misorientation inside wire bonded encapsulated Low-profile Fine-pitch Ball Grid Array (LFPGA) packages. B-XRDI is an x-ray diffraction imaging technique which allows the user to reconstruct from a series of section x-ray topographic images a full profile of the warpage of the silicon semiconductor die inside such a chip package. There is no requirement for pre-treatment or pre-processing of the chip package and we show that synchrotron-based B-XRDI mapping of wafer warpage can be achieved with angular tilt resolutions of the order of 50 μrad ≈ 0.003° in times as short as 9–180 s (worst case X–Y spatial resolution = 100 μm) for a full 8.7 mm × 8.7 mm semiconductor die inside the fully encapsulated LFBGA packages. We confirm the usefulness of the technique by correlating our data with conventional warpage measurements performed by mechanical and interferometric profilometry and finite element modelling (FEM). We suggest that future developments will lead to real-time, or near real-time, mapping of thermomechanical stresses during chip packaging processes, which can run from bare wafer through to a fully encapsulated chip package.	Apr 2016
B16-Test Beamline	Nondestructive monitoring of die warpage in encapsulated chip packages A. Bose , R. K. Vijayaraghavan , A Cowley , V. Cherman , Olalla Varela Pedreira , B K Tanner , A. N. Danilewsky , I. De Wolf , P. J. Mcnally Ieee Transactions On Components, Packaging And Manufacturing Technology 6, 653 - 662 DOI: 10.1109/TCPMT.2016.2527060 Diamond Proposal Number(s): [9479, 10052] Show Abstract ▼ Abstract: We describe an X-ray diffraction imaging technique for nondestructive, in situ measurement of die warpage in encapsulated chip packages at acquisition speeds approaching real time. The results were validated on a series of samples with known inbuilt convex die warpage, and the measurement of wafer bow was compared with the results obtained by optical profilometry. We use the technique to demonstrate the impact of elevated temperature on a commercially sourced micro quad flat nonlead chip package and show that the strain becomes locked in at a temperature between 94 °C and 120 °C. Using synchrotron radiation at the Diamond Light Source, warpage maps for the entire $2.2~textrm {mm} times 2.4~textrm {mm} times 150$ - $mu text{m}$ Si die were acquired in 50 s, and individual line scans in times as short as 500 ms.	Mar 2016
B16-Test Beamline	X-ray asterism and the structure of cracks from indentations in silicon B. K. Tanner , J. Garagorri , E. Gorostegui-Colinas , M. R. Elizalde , D. Allen , P. J. Mcnally , J. Wittge , C. Ehlers , A. N. Danilewsky Journal Of Applied Crystallography 49, 250 - 259 DOI: 10.1107/S1600576715024620 Diamond Proposal Number(s): [7634] Show Abstract ▼ Abstract: The asterism observed in white radiation X-ray diffraction images (topographs) of extended cracks in silicon is investigated and found to be associated with material that is close to break-out and surrounded by extensive cracking. It is a measure of the mechanical damage occurring when the fracture planes do not follow the low index cleavage planes associated with the crystal structure. It is not related to a propensity for some cracked wafers to shatter during subsequent high temperature processing. There is no correlation between crack morphology and alignment of an indenter with respect to the orientation of a silicon wafer, the cracks being generated from the apices of the indenter and having three-fold symmetry for Berkovich indents and four-fold symmetry for Vickers indents. X-ray diffraction images (XRDI) of indents do not reveal this underlying symmetry and exhibit a very substantial degree of variation in their extent. These arise because the XRDI contrast is sensitive to the long range strain field around the indent and break-out reduces the extent of this long rage strain field. Break-out is also detected in the loss of symmetry in the short range strain field imaged by scanning micro-Raman spectroscopy. Weak four-fold symmetric features at the extremes of the images, and lying along <110> directions, are discussed in the context of slip generated below the room-temperature indents. Scanning electron microscopy imaging of the region around an indent during focused ion beam milling has permitted the three dimensional reconstruction of the crack morphology. The surface-breaking Palmqvist cracks are found to be directly connected to the median sub-surface cracks and the presence of extensive lateral cracks is a prerequisite for material break-out at indenter loads above 200 mN. The overall crack shape agrees with that predicted from simulation.	Feb 2016

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