Kultaransingh Hooghan - Academia.edu (original) (raw)

Papers by Kultaransingh Hooghan

Research paper thumbnail of Extended Abstract: Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-Ion Milled Samples

E lectron microscopic examination of pores within mudrocks (shales and mudstones) has become much... more E lectron microscopic examination of pores within mudrocks (shales and mudstones) has become much more sophisticated over the last few years, driven not only by the intense economic interest in shale gas and oil, but also by the technological improvements that allow characterization of nanometer-scale features. In the last five years, electron microscopy techniques have evolved sufficiently to allow researchers to identify and quantify nanometer-scale pores. Previous studies characterized mudstone porosity by documenting the frequency distribution of pore sizes. This was done by comparing maximum pore diameters (Loucks et al., 2009) and by analyzing pore volumes (Sondergeld et al., 2010).

Research paper thumbnail of JME Referees in 1994

Journal of Moral Education, 1995

Journal of Moral Education, Vol. 24, No. 2, 1995 ... In addition to the Editorial Board, the foll... more Journal of Moral Education, Vol. 24, No. 2, 1995 ... In addition to the Editorial Board, the following have also acted as referees in 1994: ... Henry Alexander University of Judaism, California, USA Michael Bond Chinese University of Hong Kong, Hong Kong Muriel Bebeau University of ...

Research paper thumbnail of Failure Analysis of Flip-Chip Bumps After Thermal Stressing

<jats:title>Abstract</jats:title> <jats:p>This paper describes a new diagnostic... more <jats:title>Abstract</jats:title> <jats:p>This paper describes a new diagnostic technique for analyzing microstructural changes occurring to flip chip joints after accelerated thermal tests. Flip chip reliability was assessed at high temperatures, with and without the application of electrical bias. A combination of standard metallurgical polishing techniques and the use of a focused ion beam (FIB) lift out technique was employed to make site-specific samples for transmission electron microscopy (TEM) cross-sections. We studied evaporated 95Pb/5Sn bumps, on sputtered Cr/CrCu/Cu/Au as the under bump metallization (UBM). Thermally stressed samples were tested for electrical continuity and evaluated using 50 MHz C-mode scanning acoustic microscopy (C-SAM). Failed samples were crosssectioned and large voids at the UBM were observed optically. TEM specimens taken from the predefined UBM region of degraded flip chip devices provided critical microstructural information, which led to a better understanding of a cause of degradation occurring in the flip chip joints.</jats:p>

Research paper thumbnail of The International Cartographic Association – Progress during 1991–95

The Cartographic Journal, 1995

Research paper thumbnail of Pore-Scale Imaging of Solid Bitumens: Insights for Unconventional Reservoir Characterization

Memoir 120: Mudstone Diagenesis: Research Perspectives for Shale Hydrocarbon Reservoirs, Seals, and Source Rocks, 2019

Characterizing unconventional reservoirs involves the investigation of a wide range of potential ... more Characterizing unconventional reservoirs involves the investigation of a wide range of potential source rock targets at various stages of thermal maturity. These samples may contain a mixture of kerogen, bitumen, oil and pyrobitumen within their fabric. Thus, it is critical that we properly identify and examine each organic phase in order to better understand reservoir properties. In the present study, we have selected samples of gilsonite from a naturally occurring solid hydrocarbon deposit to serve as an analog for characterizing the bitumen phase of generation.

Research paper thumbnail of Petroleum Geochemistry and Mudstone Diagenesis of the Woodford Shale, Anadarko Basin, USA – An Integrated Approach

We undertook an integrated organic geochemical and petrologic study of the Upper Devonian­ Lower ... more We undertook an integrated organic geochemical and petrologic study of the Upper Devonian­ Lower Mississippian Woodford Shale on cores recovered from thermally mature and liquids-rich mudstone reservoirs in the Anadarko basin of south-central Oklahoma, USA. The purpose of the work was to identify the critical mechanisms that control oil and natural gas generation, expulsion, migration, and retention in an active petroleum source rock that is also a producing unconventional reservoir. We identified five microfacies in the Woodford Shale; 1) siliceous mudstone; 2) silicified mudstone; 3) chert and argillaceous chert; 4) argillaceous, siliceous dolostone; and 5) phosphatic mudstone. All ofthese microfacies exceed the minimum TOC and S2 threshold values for effective petroleum source rocks. The original hydrogen index (ill) values, calculated from visual kerogen data, indicate oil-prone organic matter in the rocks. Thermal maturity approximates the boundary between low-volatile and high...

Research paper thumbnail of 12 Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-ion-milled Samples

The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus... more The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus, and Barnett shale samples was similar when comparing relative numerical abundances of maximum pore diameters but not when comparing relative abundances of pore areas (pore sizes). Differences also existed between units in the association of pores with organic material. Pores were measured on argon-ion-milled (AIM) samples and examined with a field emission environmental scanning electron microscope (SEM). One Haynesville sample was also evaluated using a focused ion beam (FIB) SEM to compare to the AIM results. With the AIM samples, pore types were subdivided into three categories—organic pores, mixed matrix/organic pores, and matrix pores—based on the amount and type of material (organic or inorganic) surrounding the pores. Organic pores are pores generally associated with kerogen macerals, whereas mixed matrix/organic pores are pores that are probably associated with bitumen or pyrob...

Research paper thumbnail of Deciphering Liquid Metal Embrittlement and Altered FIB Damage Microstructures on Aluminum

Microscopy and Microanalysis

Focused ion beam milling has advanced site-specific TEM and atom probe tomography (APT) sample pr... more Focused ion beam milling has advanced site-specific TEM and atom probe tomography (APT) sample preparation for analysis of grain boundaries, precipitates, or other features of interest, as well as allowing for 3D cross-sectioning at high rates to allow for depth profile investigations [1-4, 8]. With the rise of insitu TEM mechanical testing, there is a need to fabricate nano-specimens for testing. Focused Ion Beams (FIBs) are most commonly used for micro-machining and patterning and used for prepared specimens via nanomilling and nanomanipulation) [2]. However, there are issues with liquid metal (LM)-based ion sources in certain materials. FIB milling can amorphize materials introducing a damage layer and can result in Ga implantation contamination in certain materials. This has been observed in grain and phase boundaries of certain materials, such as semiconductors and some metals [8, 9]. Nanomilling of specimens is necessary for thinning of material for TEM-transparency (~100nm thick). Milling at these dimensions and angles induces damage, some of which can be protected/mitigated, some of which cannot. Trace concentrations of impurities at grain boundaries can impact grain growth and mechanical properties. Gallium diffusion in Al occurs with Ga as a liquid at room temperature, and can diffuse rapidly to existing defects, primarily grain boundaries [4]. Grain boundaries and grain boundary character (composition, orientation) greatly influence mechanical properties [10]. Aluminum (Al) has been shown to be embrittled by gallium (Ga) implantation and inclusion in the matrix, as liquid Ga penetrates the matrix [4]. In addition to ion implantation, ion irradiation can cause the development of knock-on damage, such as defects (loops and black dot damage) and amorphization, both of which occur on the nanometer scale but contribute to overall bulk material properties [1-3, 5]. In addition, phase changes can occur in other multi-component material systems [6].

Research paper thumbnail of Multi-modal SEM Imaging for Shale Reservoir Characterization

Microscopy and Microanalysis

2. Weatherford International Recent advances in imaging technologies have allowed us to interroga... more 2. Weatherford International Recent advances in imaging technologies have allowed us to interrogate materials at progressively higher resolutions over larger areas or volumes of sample. As we have begun to investigate geomaterials at resolutions on the single nanometer scale, our observations have upended several long-lived paradigms of geoscience. This has proved particularly true in shale reservoirs. Although it is fascinating to continue to look more deeply into these reservoirs, we are also faced with three daunting challenges. The first involves development of standard protocols for imaging. As we push the limits of our imaging tools, the details of sample preparation, the composition and thickness of conductive coatings, the configuration of the electron column, the excitation voltage and choice of electron signal to use for imaging, and the pre-and post-processing of image data all influence the results of our analyses. The second challenge involves the processing of extremely large volumes of image data. Individual images can be larger than 100 gigabytes in size, too large for many of the existing tools for image analysis to open and segment. The third challenge, involves the upscaling of our observations from the nanometer scale of the pore space to the vertical thickness of the formation (hundreds of meters) and the basin scale (hundreds of kilometers). This paper presents an evaluation of how the details of sample preparation, image acquisition, and image processing influence the results of porosity and Total Organic Carbon (TOC) analysis from SEM image data in shale reservoirs.

Research paper thumbnail of Microstructural Analysis of the Transformation of Organic Matter during Artificial Thermal Maturation of the Upper Cretaceous Boquillas (Eagle Ford) Formation, Texas, USA

Microscopy and Microanalysis

Research paper thumbnail of Organic Matter Characterization in Shales: A Systematic Empirical Protocol

Microscopy and Microanalysis

Research paper thumbnail of Fabricating semiconductor chips

Research paper thumbnail of Method and apparatus for disabling an integrated circuit (IC) when an attempt is made to bypass security on the IC

Research paper thumbnail of Physical Failure Analysis techniques for Cu/low k technology

Proceedings of the 10th International Symposium on the Physical and Failure Analysis of Integrated Circuits. IPFA 2003, 2003

ABSTRACT In this work, physical FA techniques including deprocessing and cross section analysis h... more ABSTRACT In this work, physical FA techniques including deprocessing and cross section analysis have been developed and applied to Cu/low k technology. Deprocessing techniques discussed include: wet chemical etching, reactive ion etching (RIE), parallel polishing, chemical mechanical polishing (CMP) and combination of these techniques. For the cross-section analysis of copper/low k samples, focused ion beam and mechanical polishing techniques have been developed and studied. Failure Analysis (FA) challenges and new failure modes, reliability issues will also be addressed.

Research paper thumbnail of Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-ion-milled Samples

The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus... more The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus, and Barnett shale samples was similar when comparing relative numerical abun-dances of maximum pore diameters but not when comparing relative abundances of pore areas (pore sizes). Differences also existed between units in the association of pores with or-ganic material. Pores were measured on argon-ion-milled (AIM) samples and examined with a field emission environmental scanning electron microscope (SEM). One Haynesville sample was also evaluated using a focused ion beam (FIB) SEM to compare to the AIM results. With the AIM samples, pore types were subdivided into three categories—organic pores, mixed matrix/organic pores, and matrix pores—based on the amount and type of material (organic or inorganic) surrounding the pores. Organic pores are pores generally associated with kero-gen macerals, whereas mixed matrix/organic pores are pores that are probably associated with bitumen or py...

Research paper thumbnail of The Effects of Board Attachment Processing on Sn Whisker Formation on Electroplated Matte-Sn on Cu Alloy Lead Frames

The effects of a simulated solder reflow attach process on the propensity for Sn-whisker formatio... more The effects of a simulated solder reflow attach process on the propensity for Sn-whisker formation and growth of plated matte-Sn on Cu alloy lead frames was studied. The application of a post-plate solder reflow process has been found to essentially negate the beneficial effects researchers have previously observed through the usage of thicker matte-Sn plates and with the application of a post- plate anneal of 150C for 1 hour of as-made Sn-plates. Fine long-needle like whiskers are found to grow on reflowed matte-Sn on trim and formed Cu leads, with or without a post plate bake, after aging at a condition of 60C/93%RH. The mechanism for the formation of the Sn-whiskers is related to the break down and dissolution of the Cu/Sn intermetallics, followed by precipitation and growth of Cu/Sn intermetallics at grain boundaries and other low energy interfaces, this leads to the initiation and growth of the whiskers within the bulk of the reflowed Sn plate. These fine long-narrow whiskers a...

Research paper thumbnail of Tin Whisker Mitigation: Application of Post Mold Nickel Underplate on Copper Based Lead Frames and Effects of Board Assembly Reflow

In spite almost 6 decades of research on Sn-whisker formation and growth, neither atomistic and e... more In spite almost 6 decades of research on Sn-whisker formation and growth, neither atomistic and empirical models that can be used to predict when, where, and at what time Sn-whiskers might occur on electrical devices that use Sn on Cu metallization for electrical interconnection are available. Furthermore, results reported by different researchers vary significantly. Because predictive models for Sn-whisker growth are not yet fully developed, we choose to take a statistical approach to the problem. To do so, we evaluated the propensity for whisker formation and growth on trim and formed devices that had matte- Sn plated leads where the Sn-plate was varied via: i)different Sn plating chemistries and bath suppliers; and ii) different suppliers of plated leads frame devices. In addition, different lead frame Cu alloys (7025 and 194) and different package types, as well as devices with and without Ni-underplate between the Cu and Sn were used in the study. Finally, devices with and with...

Research paper thumbnail of Protocol for Finalizing Locations for FIB/SEM Cubes on Shale Samples: General Guidelines with Up Scaling in Mind

Proceedings of the 2nd Unconventional Resources Technology Conference, 2014

Research paper thumbnail of Use of Digital Imaging for Improved Evaluation of Unconventional Reservoirs

SPE Reservoir Characterization and Simulation Conference and Exhibition, 2013

Research paper thumbnail of Observation of amorphous chromium in modified C4 flip chip solder joints after thermal stress testing

Thin Solid Films, 2003

Flip chip reliability was evaluated using thermal stress tests at 150 8C. Electrical failures of ... more Flip chip reliability was evaluated using thermal stress tests at 150 8C. Electrical failures of flip chip devices were found to occur at the solderyunder-bump-metallization interface by forming a porous amorphous chromium layer. The formation of the porous amorphous layer responsible for electrical failures resulted from the outdiffusion of copper atoms from a copper-chromium co-deposit, used as one of the under-bump-metallization layers. A strong interaction of Cu with the Sn component of the solder is the driving force of the Cu outdiffusion.

Research paper thumbnail of Extended Abstract: Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-Ion Milled Samples

E lectron microscopic examination of pores within mudrocks (shales and mudstones) has become much... more E lectron microscopic examination of pores within mudrocks (shales and mudstones) has become much more sophisticated over the last few years, driven not only by the intense economic interest in shale gas and oil, but also by the technological improvements that allow characterization of nanometer-scale features. In the last five years, electron microscopy techniques have evolved sufficiently to allow researchers to identify and quantify nanometer-scale pores. Previous studies characterized mudstone porosity by documenting the frequency distribution of pore sizes. This was done by comparing maximum pore diameters (Loucks et al., 2009) and by analyzing pore volumes (Sondergeld et al., 2010).

Research paper thumbnail of JME Referees in 1994

Journal of Moral Education, 1995

Journal of Moral Education, Vol. 24, No. 2, 1995 ... In addition to the Editorial Board, the foll... more Journal of Moral Education, Vol. 24, No. 2, 1995 ... In addition to the Editorial Board, the following have also acted as referees in 1994: ... Henry Alexander University of Judaism, California, USA Michael Bond Chinese University of Hong Kong, Hong Kong Muriel Bebeau University of ...

Research paper thumbnail of Failure Analysis of Flip-Chip Bumps After Thermal Stressing

<jats:title>Abstract</jats:title> <jats:p>This paper describes a new diagnostic... more <jats:title>Abstract</jats:title> <jats:p>This paper describes a new diagnostic technique for analyzing microstructural changes occurring to flip chip joints after accelerated thermal tests. Flip chip reliability was assessed at high temperatures, with and without the application of electrical bias. A combination of standard metallurgical polishing techniques and the use of a focused ion beam (FIB) lift out technique was employed to make site-specific samples for transmission electron microscopy (TEM) cross-sections. We studied evaporated 95Pb/5Sn bumps, on sputtered Cr/CrCu/Cu/Au as the under bump metallization (UBM). Thermally stressed samples were tested for electrical continuity and evaluated using 50 MHz C-mode scanning acoustic microscopy (C-SAM). Failed samples were crosssectioned and large voids at the UBM were observed optically. TEM specimens taken from the predefined UBM region of degraded flip chip devices provided critical microstructural information, which led to a better understanding of a cause of degradation occurring in the flip chip joints.</jats:p>

Research paper thumbnail of The International Cartographic Association – Progress during 1991–95

The Cartographic Journal, 1995

Research paper thumbnail of Pore-Scale Imaging of Solid Bitumens: Insights for Unconventional Reservoir Characterization

Memoir 120: Mudstone Diagenesis: Research Perspectives for Shale Hydrocarbon Reservoirs, Seals, and Source Rocks, 2019

Characterizing unconventional reservoirs involves the investigation of a wide range of potential ... more Characterizing unconventional reservoirs involves the investigation of a wide range of potential source rock targets at various stages of thermal maturity. These samples may contain a mixture of kerogen, bitumen, oil and pyrobitumen within their fabric. Thus, it is critical that we properly identify and examine each organic phase in order to better understand reservoir properties. In the present study, we have selected samples of gilsonite from a naturally occurring solid hydrocarbon deposit to serve as an analog for characterizing the bitumen phase of generation.

Research paper thumbnail of Petroleum Geochemistry and Mudstone Diagenesis of the Woodford Shale, Anadarko Basin, USA – An Integrated Approach

We undertook an integrated organic geochemical and petrologic study of the Upper Devonian­ Lower ... more We undertook an integrated organic geochemical and petrologic study of the Upper Devonian­ Lower Mississippian Woodford Shale on cores recovered from thermally mature and liquids-rich mudstone reservoirs in the Anadarko basin of south-central Oklahoma, USA. The purpose of the work was to identify the critical mechanisms that control oil and natural gas generation, expulsion, migration, and retention in an active petroleum source rock that is also a producing unconventional reservoir. We identified five microfacies in the Woodford Shale; 1) siliceous mudstone; 2) silicified mudstone; 3) chert and argillaceous chert; 4) argillaceous, siliceous dolostone; and 5) phosphatic mudstone. All ofthese microfacies exceed the minimum TOC and S2 threshold values for effective petroleum source rocks. The original hydrogen index (ill) values, calculated from visual kerogen data, indicate oil-prone organic matter in the rocks. Thermal maturity approximates the boundary between low-volatile and high...

Research paper thumbnail of 12 Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-ion-milled Samples

The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus... more The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus, and Barnett shale samples was similar when comparing relative numerical abundances of maximum pore diameters but not when comparing relative abundances of pore areas (pore sizes). Differences also existed between units in the association of pores with organic material. Pores were measured on argon-ion-milled (AIM) samples and examined with a field emission environmental scanning electron microscope (SEM). One Haynesville sample was also evaluated using a focused ion beam (FIB) SEM to compare to the AIM results. With the AIM samples, pore types were subdivided into three categories—organic pores, mixed matrix/organic pores, and matrix pores—based on the amount and type of material (organic or inorganic) surrounding the pores. Organic pores are pores generally associated with kerogen macerals, whereas mixed matrix/organic pores are pores that are probably associated with bitumen or pyrob...

Research paper thumbnail of Deciphering Liquid Metal Embrittlement and Altered FIB Damage Microstructures on Aluminum

Microscopy and Microanalysis

Focused ion beam milling has advanced site-specific TEM and atom probe tomography (APT) sample pr... more Focused ion beam milling has advanced site-specific TEM and atom probe tomography (APT) sample preparation for analysis of grain boundaries, precipitates, or other features of interest, as well as allowing for 3D cross-sectioning at high rates to allow for depth profile investigations [1-4, 8]. With the rise of insitu TEM mechanical testing, there is a need to fabricate nano-specimens for testing. Focused Ion Beams (FIBs) are most commonly used for micro-machining and patterning and used for prepared specimens via nanomilling and nanomanipulation) [2]. However, there are issues with liquid metal (LM)-based ion sources in certain materials. FIB milling can amorphize materials introducing a damage layer and can result in Ga implantation contamination in certain materials. This has been observed in grain and phase boundaries of certain materials, such as semiconductors and some metals [8, 9]. Nanomilling of specimens is necessary for thinning of material for TEM-transparency (~100nm thick). Milling at these dimensions and angles induces damage, some of which can be protected/mitigated, some of which cannot. Trace concentrations of impurities at grain boundaries can impact grain growth and mechanical properties. Gallium diffusion in Al occurs with Ga as a liquid at room temperature, and can diffuse rapidly to existing defects, primarily grain boundaries [4]. Grain boundaries and grain boundary character (composition, orientation) greatly influence mechanical properties [10]. Aluminum (Al) has been shown to be embrittled by gallium (Ga) implantation and inclusion in the matrix, as liquid Ga penetrates the matrix [4]. In addition to ion implantation, ion irradiation can cause the development of knock-on damage, such as defects (loops and black dot damage) and amorphization, both of which occur on the nanometer scale but contribute to overall bulk material properties [1-3, 5]. In addition, phase changes can occur in other multi-component material systems [6].

Research paper thumbnail of Multi-modal SEM Imaging for Shale Reservoir Characterization

Microscopy and Microanalysis

2. Weatherford International Recent advances in imaging technologies have allowed us to interroga... more 2. Weatherford International Recent advances in imaging technologies have allowed us to interrogate materials at progressively higher resolutions over larger areas or volumes of sample. As we have begun to investigate geomaterials at resolutions on the single nanometer scale, our observations have upended several long-lived paradigms of geoscience. This has proved particularly true in shale reservoirs. Although it is fascinating to continue to look more deeply into these reservoirs, we are also faced with three daunting challenges. The first involves development of standard protocols for imaging. As we push the limits of our imaging tools, the details of sample preparation, the composition and thickness of conductive coatings, the configuration of the electron column, the excitation voltage and choice of electron signal to use for imaging, and the pre-and post-processing of image data all influence the results of our analyses. The second challenge involves the processing of extremely large volumes of image data. Individual images can be larger than 100 gigabytes in size, too large for many of the existing tools for image analysis to open and segment. The third challenge, involves the upscaling of our observations from the nanometer scale of the pore space to the vertical thickness of the formation (hundreds of meters) and the basin scale (hundreds of kilometers). This paper presents an evaluation of how the details of sample preparation, image acquisition, and image processing influence the results of porosity and Total Organic Carbon (TOC) analysis from SEM image data in shale reservoirs.

Research paper thumbnail of Microstructural Analysis of the Transformation of Organic Matter during Artificial Thermal Maturation of the Upper Cretaceous Boquillas (Eagle Ford) Formation, Texas, USA

Microscopy and Microanalysis

Research paper thumbnail of Organic Matter Characterization in Shales: A Systematic Empirical Protocol

Microscopy and Microanalysis

Research paper thumbnail of Fabricating semiconductor chips

Research paper thumbnail of Method and apparatus for disabling an integrated circuit (IC) when an attempt is made to bypass security on the IC

Research paper thumbnail of Physical Failure Analysis techniques for Cu/low k technology

Proceedings of the 10th International Symposium on the Physical and Failure Analysis of Integrated Circuits. IPFA 2003, 2003

ABSTRACT In this work, physical FA techniques including deprocessing and cross section analysis h... more ABSTRACT In this work, physical FA techniques including deprocessing and cross section analysis have been developed and applied to Cu/low k technology. Deprocessing techniques discussed include: wet chemical etching, reactive ion etching (RIE), parallel polishing, chemical mechanical polishing (CMP) and combination of these techniques. For the cross-section analysis of copper/low k samples, focused ion beam and mechanical polishing techniques have been developed and studied. Failure Analysis (FA) challenges and new failure modes, reliability issues will also be addressed.

Research paper thumbnail of Comparison of Porosity Distribution within Selected North American Shale Units by SEM Examination of Argon-ion-milled Samples

The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus... more The distribution of nanometer-size pores in ten selected Eagle Ford Group, Haynesville, Marcellus, and Barnett shale samples was similar when comparing relative numerical abun-dances of maximum pore diameters but not when comparing relative abundances of pore areas (pore sizes). Differences also existed between units in the association of pores with or-ganic material. Pores were measured on argon-ion-milled (AIM) samples and examined with a field emission environmental scanning electron microscope (SEM). One Haynesville sample was also evaluated using a focused ion beam (FIB) SEM to compare to the AIM results. With the AIM samples, pore types were subdivided into three categories—organic pores, mixed matrix/organic pores, and matrix pores—based on the amount and type of material (organic or inorganic) surrounding the pores. Organic pores are pores generally associated with kero-gen macerals, whereas mixed matrix/organic pores are pores that are probably associated with bitumen or py...

Research paper thumbnail of The Effects of Board Attachment Processing on Sn Whisker Formation on Electroplated Matte-Sn on Cu Alloy Lead Frames

The effects of a simulated solder reflow attach process on the propensity for Sn-whisker formatio... more The effects of a simulated solder reflow attach process on the propensity for Sn-whisker formation and growth of plated matte-Sn on Cu alloy lead frames was studied. The application of a post-plate solder reflow process has been found to essentially negate the beneficial effects researchers have previously observed through the usage of thicker matte-Sn plates and with the application of a post- plate anneal of 150C for 1 hour of as-made Sn-plates. Fine long-needle like whiskers are found to grow on reflowed matte-Sn on trim and formed Cu leads, with or without a post plate bake, after aging at a condition of 60C/93%RH. The mechanism for the formation of the Sn-whiskers is related to the break down and dissolution of the Cu/Sn intermetallics, followed by precipitation and growth of Cu/Sn intermetallics at grain boundaries and other low energy interfaces, this leads to the initiation and growth of the whiskers within the bulk of the reflowed Sn plate. These fine long-narrow whiskers a...

Research paper thumbnail of Tin Whisker Mitigation: Application of Post Mold Nickel Underplate on Copper Based Lead Frames and Effects of Board Assembly Reflow

In spite almost 6 decades of research on Sn-whisker formation and growth, neither atomistic and e... more In spite almost 6 decades of research on Sn-whisker formation and growth, neither atomistic and empirical models that can be used to predict when, where, and at what time Sn-whiskers might occur on electrical devices that use Sn on Cu metallization for electrical interconnection are available. Furthermore, results reported by different researchers vary significantly. Because predictive models for Sn-whisker growth are not yet fully developed, we choose to take a statistical approach to the problem. To do so, we evaluated the propensity for whisker formation and growth on trim and formed devices that had matte- Sn plated leads where the Sn-plate was varied via: i)different Sn plating chemistries and bath suppliers; and ii) different suppliers of plated leads frame devices. In addition, different lead frame Cu alloys (7025 and 194) and different package types, as well as devices with and without Ni-underplate between the Cu and Sn were used in the study. Finally, devices with and with...

Research paper thumbnail of Protocol for Finalizing Locations for FIB/SEM Cubes on Shale Samples: General Guidelines with Up Scaling in Mind

Proceedings of the 2nd Unconventional Resources Technology Conference, 2014

Research paper thumbnail of Use of Digital Imaging for Improved Evaluation of Unconventional Reservoirs

SPE Reservoir Characterization and Simulation Conference and Exhibition, 2013

Research paper thumbnail of Observation of amorphous chromium in modified C4 flip chip solder joints after thermal stress testing

Thin Solid Films, 2003

Flip chip reliability was evaluated using thermal stress tests at 150 8C. Electrical failures of ... more Flip chip reliability was evaluated using thermal stress tests at 150 8C. Electrical failures of flip chip devices were found to occur at the solderyunder-bump-metallization interface by forming a porous amorphous chromium layer. The formation of the porous amorphous layer responsible for electrical failures resulted from the outdiffusion of copper atoms from a copper-chromium co-deposit, used as one of the under-bump-metallization layers. A strong interaction of Cu with the Sn component of the solder is the driving force of the Cu outdiffusion.